Best Smart Lock for Secure, Keyless Front Door Entry

About the author...

Dave has been taking gadgets apart since he was old enough to be told not to. Every pick here is checked against the manufacturer's own documentation rather than the retail listing, and each star rating starts from a product's real Amazon customer score before being adjusted for performance, build quality, features and value. Read more about how ratings are calculated.

The best smart lock overall is the eufy Security Smart Lock C220. It backs up a sub-second fingerprint reader with an 8-month battery life, and it doesn't need a separate bridge to work.¹ Nine more alternatives below cover a faster, better-certified retrofit cylinder lock, a built-in video doorbell, a keypad-only option that skips the app entirely, a fingerprint lock with real backup power, a smart handle for doors that take a lever rather than a cylinder, a non-invasive overlay that keeps your existing keys, a budget fingerprint retrofit, a weatherproof lever handle for exposed doors, and the highest-certified deadbolt in the lineup.

A smart lock replaces or retrofits your front door's existing mechanism. It can then be opened with a code, a fingerprint, a phone, or a key card, instead of a physical key or alongside one. The appeal is straightforward: no more spare keys hidden under a mat, no more re-keying the whole house when a housemate moves out, and a log of who came and went. But this category sells itself on convenience. The thing actually protecting your home is a mechanical cylinder or bolt underneath the electronics, and that part varies enormously between products carrying near-identical marketing copy.

What separates a good smart lock from a disappointing one usually isn't the app. It's whether the lock fits the door you actually have. It's whether the underlying hardware carries a real independent security certification, rather than just a manufacturer's claim. And it's whether the battery genuinely lasts as long as advertised once you're using fingerprint scans or a camera, not just a single push-button. A lock that looks sleek in photos but drops its Wi-Fi connection weekly isn't the bargain the listing price suggests. Neither is one that needs a separately priced accessory just to work with your phone.

Key Takeaways (TL;DR)

• Match the lock to your door prep first, not the brand. Euro cylinder, nightlatch, and standard bore-and-backset doors each need a different lock design, and they're rarely interchangeable.
• Fingerprint speed and storage capacity vary a lot. Look for sub-second recognition and at least 50 stored prints if more than one or two people will use the lock.
• "Works with an app" doesn't always mean out of the box. Some locks need a separately sold hub or access module before remote control or voice assistants work at all.
• An independent cylinder certification, like SKG or EN 1303, tells you far more about forced-entry resistance than marketing language does.
• Battery claims are best-case figures. Real-world use, especially with fingerprint scanning or a built-in camera running, typically falls short of the printed number.
• A camera-equipped lock adds real value but also a storage decision. Check whether footage stays on the device or needs a cloud subscription before you rely on it.
• Keep a mechanical backup regardless of which lock you buy - a physical key, a second keypad code, or an external battery terminal - for the day the main battery finally dies.

How We Choose

Each lock is scored on how reliably it recognises the fingerprint, code, or app command it's asked to check. We also weigh how the cylinder or bolt mechanism and its housing hold up against wear and forced entry, and whether extra features like a camera, backup power, or NFC are genuinely useful rather than padding. Price is judged against the other five products in this list, not the whole market, since the smart lock category runs from budget keypads to premium retrofit cylinders from long-established lock manufacturers. Battery life, certifications, and connectivity claims are checked against each manufacturer's own spec page or independent lab testing where available. Amazon bullet points are often copied from a different regional variant of the same model, so they're treated as a starting point, not a source.

We don't run our own lab tests on these — no dedicated rig, no controlled conditions. What we do instead: read through the verified-purchase reviews in full, not just the star average, weighting the ones written weeks or months after purchase over launch-week first impressions, since that's where wear, reliability problems, and real-world performance gaps actually show up. Where a product genuinely lacks that kind of track record, we say so in its write-up rather than papering over it.

Quick Comparison

Each product's overall rating starts from its real Amazon customer rating, then gets adjusted (up to ±0.5) for real-world performance, build quality, features, and value. Click a product name to jump straight to its full review below.

eufy Security Smart Lock C220

Best Overall

based on 3870 Amazon reviews (4.3★), adjusted for performance, build and value

What We Love About the Overall Pick

This is the lock to reach for if you just want one that does everything well, without extra shopping. eufy's own spec page confirms fingerprint recognition in under 0.3 seconds. It also confirms storage for up to 50 fingerprints and 100 separate passcodes, enough for a full household plus regular visitors.¹ Wi-Fi is built into the lock itself, so there's no bridge or hub to buy separately. The eufy Security app handles remote locking, activity logs, and access management directly. It's also the most-reviewed smart lock in this entire roundup, by a wide margin, which matters in a category with plenty of short-lived listings. The advertised 8-month battery life doesn't always hold up, though: one buyer running two units on a pair of remote apartment doors reported one battery dying after 4 weeks and the other after 6, and only got the advertised runtime after switching to lithium batteries on eufy's advice.

Overall Pick: All The Details

Check one thing before adding this to your basket. It's built to replace a standard single-cylinder deadbolt, the bore-and-backset format most common on North American doors, not a euro profile cylinder or a rim-mounted nightlatch. If your front door uses one of those instead, skip to the Nuki, SwitchBot, or Yale picks further down this list. The C220 runs on 8 AA batteries, rated for roughly 8 months of typical use. eufy backs the housing with an IP53 rating against dust and light water spray, so it suits a covered porch rather than direct driving rain.¹ It also carries BHMA Grade 3 certification, the entry-level tier of the American residential lock testing standard covering cycle and impact resistance. That's built to withstand daily use for years rather than decades.² Entry methods include fingerprint, the app, a physical key, and a backup keypad. Setup needs no rewiring, and eufy covers the lock with an 18-month warranty plus ongoing customer support.

Nuki Smart Lock Ultra

Best Premium Pick

based on 556 Amazon reviews (4.5★), adjusted for performance, build and value

Why the Premium Pick Earns Its Price

Nuki builds this lock around its Universal Cylinder. That cylinder carries SKG*** certification and meets EN 1303, the European standard used for cylinder locks across many countries.³ SKG*** is an independent Dutch security rating. It confirms the cylinder resists sustained mechanical attack with heavy tools for at least five minutes, a higher, time-based bar than the entry-level BHMA Grade 3 certification carried by the two eufy locks in this roundup.⁴ A new brushless motor backs that certification with real speed. Independent testing measured unlock times of well under two seconds in the fastest of the lock's three selectable speed modes.⁵ One owner who waited a few months before reviewing it, specifically to avoid an overly hasty verdict, said they'd been "using it for a good few months now and wouldn't go back to a normal lock."

Premium Pick: All The Details

Installation takes around 15 minutes, with no drilling, since the Universal Cylinder swaps into most existing multi-point and cylinder doors.³ The built-in rechargeable battery recharges fully in about two hours over a magnetic cable. Nuki rates it for roughly six months per charge, though an independent reviewer running it in a busy four-person household saw a little over five months in practice. That's a reasonable, honestly disclosed gap between marketing and real use.⁵ Connectivity runs over Bluetooth, built-in Wi-Fi, and Matter over Thread, working with Apple Home, Google Home, Amazon Alexa, and Samsung SmartThings without a separate bridge.⁵ It's the smallest lock in this lineup, at just 57mm across, and the most expensive. That price is the tradeoff for the strongest certified cylinder here.

Yale Smart Living Keyless Connected Ready Smart Door Lock

Best Budget Pick

based on 1096 Amazon reviews (4.1★), adjusted for performance, build and value

The Case for Skipping the App

Not everyone wants a smart lock tied to a phone app. This Yale is built for exactly that buyer. Out of the box it works entirely standalone. A PIN code, a key card, a key tag, or a remote fob all open it, with no account, no subscription, and no Wi-Fi connection required.⁶ Yale's own product page is upfront that remote access and voice assistant support only arrive if you buy a separate Yale Access Module. That's worth knowing before purchase rather than after.⁶ For anyone who just wants to stop worrying about a physical key, without adding another smart home account to manage, that tradeoff is a feature, not a limitation. That mechanical simplicity isn't a guarantee against failure, though: one buyer reported that after "a month of faultless use," the internal bolt stopped properly connecting to the handle, though a replacement arrived from Amazon the very next day.

Budget Pick: All The Details

This is a nightlatch replacement, built for a standard 60mm backset. It's powered by four AA batteries, with a 9V terminal on the exterior as an emergency backup if they run flat.⁶ Security features include an 80dB internal tamper alarm, bank-level encryption on stored codes, and built-in handling of incorrect PIN entries.⁶ An independent review found the keypad responsive and installation straightforward for a confident DIYer. It needs a new hole drilled for the keypad cable, but reuses the existing backing plate, and the review rated it four stars overall.⁷ It carries the lowest raw Amazon rating of the six locks here, reflected honestly in its position on this list: solid for the price, but not the polished ownership experience of a lock built app-first from the start.

eufy Security Video Smart Lock E330

Best Video Doorbell Integration

based on 1175 Amazon reviews (4.2★), adjusted for performance, build and value

Answering the Door Before You Open It

None of the other locks in this roundup let you see who's outside before deciding whether to unlock. The E330 folds a doorbell camera into the lock itself, recording at 2K resolution through an f/1.6 lens. That helps it hold up reasonably well in low porch light.⁸ Dual motion sensors, one infrared and one radar, trigger a notification before anyone even presses the bell. Real-time alerts land in the eufy Security app as they happen.⁸ Ownership reports are mixed on longevity: one buyer said theirs "worked for a couple of months then stopped working," and struggled to get support once the 30-day return window had closed.

Video Pick: All The Details

Like the C220, this one is built for a standard single-cylinder deadbolt door, not a euro cylinder or nightlatch. Measure your existing hardware before ordering. Footage saves to 8GB of built-in eMMC storage on the lock itself, so there's no mandatory subscription just to review a clip. eufy also offers optional cloud backup for thumbnail previews used in push notifications.⁸ Unlocking works by fingerprint, app, keypad, voice assistant, or physical key. The whole unit runs on a 10,000mAh rechargeable battery that eufy rates at roughly three months per charge, shorter than the other eufy lock in this list since the camera and screen draw power continuously.⁸ It carries an IP65 rating, meaningfully more weatherproof than a plain lock, and the same BHMA Grade 3 mechanical certification as the C220.² The tradeoff for all that hardware is a shorter charge cycle and a firmly mid-pack Amazon rating. Weigh the camera against how often you'd actually use it.

SwitchBot WiFi Smart Lock Ultra with Touchscreen Keypad

Best for Backup Power

based on 524 Amazon reviews (4.4★), adjusted for performance, build and value

Why This One Won't Leave You Locked Out

Every lock in this roundup eventually runs its battery flat. SwitchBot's answer is a Triple Power System. A rechargeable main battery handles daily use, a separate backup battery takes over automatically while the main one charges, and an emergency supercapacitor can power a handful of unlocks even after both batteries are exhausted.⁹ The bundled touchscreen keypad adds a fingerprint sensor built to recognise the whole household, on top of NFC card and passcode entry. That gives several independent ways in if any one method fails.⁹ SwitchBot rates the main battery at nine months of typical use, around ten locks and unlocks a day, and an independent PCWorld review of the same lock reported that figure too rather than a shorter real-world number.¹⁰

Backup-Power Pick: All The Details

The lock body itself is designed for European-style locks. It fits an existing euro profile cylinder, the retrofit format most common outside North America.⁹ One detail buried in the listing's own bullet points matters more than the "WiFi" name suggests. Full Wi-Fi remote access, Matter, Alexa, and Google Assistant support all route through a separate Hub Mini, sold alongside this listing rather than built into the lock body.⁹ Without it, you still get fingerprint, keypad, and Bluetooth-range app control. You just don't get remote unlocking from outside Bluetooth range. Its reviews are positive but skew toward first-week impressions, so there's no genuinely long-term, verified-purchase account of this specific lock to cite here yet.

ULTRALOQ Latch 5 Smart Lever Lock

Best Physical Handle Design

based on 186 Amazon reviews (4.2★), adjusted for performance, build and value

Built for a Different Kind of Door

Every other lock in this list retrofits a euro cylinder or a nightlatch. This one doesn't. It's a full lever handle assembly, designed for a standard bore-and-backset door prep, the format common on North American doors rather than the cylinder-based locks used across much of the rest of the world.¹¹ If your door already takes a lever handle, that's exactly the gap this lock fills. If it doesn't, none of the other picks here will fit either, so check your door's hardware before ordering. Entry runs through the touch keypad, an NFC-enabled key fob or phone tap, a companion app over Wi-Fi and Bluetooth, and a mechanical key kept as backup.¹¹ The one detailed complaint we found about dropped connectivity wasn't confirmed as a verified purchase, so we've left it out rather than presenting it as a settled pattern; treat it as one more reason to weigh the connectivity feedback below carefully.

Handle Pick: All The Details

ULTRALOQ builds the body from zinc alloy. It's rated for roughly a year of use on four AA batteries, and stores up to 50 users and 50 codes.¹¹ Wi-Fi is built directly into the lock at 2.4GHz, so no separate hub is needed for remote access. The company backs it with an 18-month electronic warranty, plus a lifetime mechanical warranty on the physical mechanism.¹¹ It has the smallest review base and the most mixed connectivity feedback of the six locks here. Several owners report the Wi-Fi or Bluetooth link dropping every week or so, occasionally needing a battery pull to reconnect.¹² Weigh that against the genuinely distinct form factor before choosing it over a cylinder-based retrofit.

Yale Linus Smart Lock

Best Non-Invasive Retrofit

based on 362 Amazon reviews (4.1★), adjusted for performance, build and value

What We Love About the Non-Invasive Pick

Every other retrofit lock in this roundup swaps out the door's cylinder for a new one. The Linus does something different. It clips over the existing cylinder on the inside of the door. The original keys still work on the outside, and nothing about the lock's mechanical core changes. That matters most to renters, or anyone who'd rather not commit to a new cylinder for good. Installation takes around three minutes once the cylinder is confirmed compatible. Geofencing unlocks the door on its own as your phone gets close, and owners consistently single this out as the best part of daily use. One reviewer who'd run it for a while called it "so convenient not to have to look for my keys when I get home." A less happy buyer had the opposite experience. Their unit "stopped working just after a few months," still under warranty, and they described Yale's support as unresponsive when they tried to get it fixed.

Non-Invasive Pick: All The Details

Power comes from four AA batteries. Remote access, instant alerts, and voice assistant integration all need the separately sold Yale Connect Wi-Fi bridge, the same limitation SwitchBot's lock carries elsewhere in this list. Without the bridge, Bluetooth-range app control and auto-unlock still work fine. Security runs on AES and TLS encryption with two-factor account protection. Losing a phone doesn't mean losing the lock either: virtual keys can be revoked instantly from any other device. Fitting depends on the door's existing cylinder size, so check Yale's compatibility video before buying. A handful of owners needed a modular replacement cylinder alongside it to get a proper fit.

WELOCK Smart Lock TOUCA51

Best Budget Fingerprint Retrofit

based on 206 Amazon reviews (4.6★), adjusted for performance, build and value

What We Love About the Budget Fingerprint Pick

Fingerprint entry usually costs more than this. The TOUCA51 packs a fingerprint reader, a passcode keypad, RFID cards, Bluetooth app control, and a USB emergency-power port into a single euro-profile cylinder. The price sits closer to a plain keypad lock than to the premium fingerprint picks elsewhere in this roundup. It carries the highest raw Amazon rating of any product in this whole list. The underlying hardware supports up to 10 administrators and 190 more users, plenty for a shared household or a small rental. Its review section is a genuine gap, though. At the time of writing there were no reviews from the region this site's other longevity quotes are drawn from, so this one comes with an honest caveat rather than a verified long-term account.

Budget Fingerprint Pick: All The Details

It fits a euro-profile cylinder between 30mm and 70mm, adjustable without cutting. Like the Nuki and SwitchBot picks above, it installs without drilling. WELOCK rates the housing IP65 for dust and water resistance and quotes electrostatic protection to 30,000 volts, both figures stated on the product's own listing. Security runs on AES encryption for stored data and the fingerprint module itself. Remote WiFi access and Alexa voice control both need WELOCK's separately sold WiFiBox3 bridge, the same pattern as the Yale Linus and SwitchBot picks. Without it, this is a Bluetooth- and keypad-only lock. WELOCK backs the unit with a 2-year warranty and support the company describes as round-the-clock.

Simpled SF-SPS Weatherproof SlimSeries Smart Lock

Best for Exposed, Weather-Facing Doors

based on 724 Amazon reviews (4.0★), adjusted for performance, build and value

What We Love About the Weatherproof Pick

Most smart locks in this category are built for a covered porch. The SF-SPS is built for doors that actually catch rain and sun on the exterior face. Simpled rates the outer panel IP55, meaningfully more sealed against dust and water than the eufy C220's IP53.¹³ It's a slim lever-handle unit rather than a bulky cylinder replacement. It's designed to bolt onto the multi-point locking mechanisms common on aluminium and composite doors, not a North American bore-and-backset. Feedback on it is genuinely split. One long-term owner reported the lock had "been flawless since install over a year ago." But Amazon's own review summary for this listing separately notes other buyers whose units stopped working within months. Weigh this one carefully rather than treating it as a universal recommendation.

Weatherproof Pick: All The Details

The kit ships with seven unlock methods: fingerprint, passcode, phone app, Bluetooth, smartwatch, NFC tag, and an emergency mechanical key, plus optional WiFi bridge support for Alexa and Google Home.¹³ The handles are aluminium and brass rather than the zinc alloy used on most other picks here. Only the outer panel is weather-rated. Simpled is clear that the inner panel must stay dry, so this isn't a lock for a fully exposed interior face either. Simpled is a London-based company offering a 2-year warranty. Its support comes up repeatedly and favourably in owner reviews, including buyers who had replacement parts shipped after a failure inside the warranty window. Installation runs 45 to 90 minutes on most multi-point doors. It needs more hands-on fitting than any other pick here, including drilling a cable-routing hole, so budget real time for it or consider professional installation.

ULTRALOQ U-Bolt Pro Smart Lock

Best ANSI Grade 1 Certified Deadbolt

based on 9042 Amazon reviews (4.3★), adjusted for performance, build and value

What We Love About the Grade 1 Pick

The eufy C220 earlier in this list carries BHMA Grade 3, the entry tier of the American residential certification scale. The U-Bolt Pro sits at the opposite end. Its listing states it meets ANSI/BHMA Grade 1, the same commercial-level standard used on buildings well beyond ordinary homes.² It's also, by a wide margin, the most-reviewed single product in this entire roundup. A review count in the thousands gives its 4.3-star average real statistical weight. One buyer's account captures the honest tradeoff of a lock this widely sold. Theirs "worked well for about a year" with automatic firmware updates running, then the fingerprint reader stopped activating. The manufacturer's support team told them a second, still-boxed backup unit's warranty no longer applied. Too much time had passed since the original purchase date.

Grade 1 Pick: All The Details

The body is zinc alloy, rated IP65 for dust and moisture on the exterior assembly. It fits a standard North American bore-and-backset deadbolt door in roughly ten minutes with just a screwdriver. Fingerprint recognition claims 0.3-second response and stores up to 100 prints, with 50 further backup codes for guests or family. A WiFi bridge is included in this bundle, enabling Alexa, Google Assistant, SmartThings, and IFTTT control alongside the fingerprint reader, keypad, app, and physical key. ULTRALOQ backs it with a lifetime mechanical warranty and an 18-month electronic warranty. The review above is a useful reminder, though: register a purchase and test every unit promptly rather than leaving a spare in its box.

Best Smart Lock FAQ

What's the single spec people get wrong most often?

Door compatibility, not battery life or fingerprint speed. Smart locks aren't universal. A lock built for a euro profile cylinder won't fit a standard single-cylinder deadbolt door, and a nightlatch replacement won't fit either of those. Measure your existing hardware, or take a photo of it to a locksmith, before ordering anything in this category. This roundup splits across several door formats. The Nuki, SwitchBot, Yale Linus, and WELOCK TOUCA51 retrofit a euro profile cylinder, though the Linus overlays the existing one rather than replacing it. The eufy C220, E330, and ULTRALOQ U-Bolt Pro replace a standard single-cylinder deadbolt. The Yale Keyless Connected replaces a rim-mounted nightlatch, and the ULTRALOQ Latch 5 and Simpled SF-SPS are built for a lever-handle door prep instead.¹³⁶⁸⁹

Which smart lock brand is most reliable?

There's no independent, apples-to-apples reliability study covering every brand in this category. Treat any single "most reliable" claim with some skepticism, including ones on review sites that only test a handful of models. What the available evidence does show is that established brands with a genuine manufacturing and support history, the kind behind every lock in this roundup, show fewer catastrophic failure patterns than newer drop-ship listings. Reliability can also vary by model generation within the same brand. Reading recent user reviews for the exact model and colour you're about to buy is a better signal than brand reputation alone.

Schlage or Yale, which is better?

Neither wins outright, because they're built for different markets and solve different problems. Schlage's residential smart lock range centres entirely on North American single-cylinder deadbolts. It has a reputation for direct Wi-Fi connectivity built into the lock itself, and its site shows no euro-cylinder or nightlatch products for doors built to other regional standards.¹⁴ Yale manufactures separate regional lines for exactly those door types, alongside its own North American deadbolt range, and leans further into open smart home standards like Matter.⁶¹⁵ If your door takes a North American deadbolt, Schlage is worth cross-shopping directly. If it takes a euro cylinder or nightlatch, as most doors outside North America do, Yale, or one of the other cylinder-based picks in this roundup, is the more relevant comparison in the first place.

Does a higher security certification actually mean a lock is harder to force?

Yes, within what that certification tests. Know what each one actually measures. Don't assume a number-badge means the same thing across different systems. ANSI/BHMA grades residential and commercial hardware on a 1-to-3 scale. Grade 3 is the entry tier, carried by the eufy C220 and E330 in this roundup: 200,000 open/close cycles and one impact test. Grade 1 is the toughest, and it's what the ULTRALOQ U-Bolt Pro is built to: 800,000 cycles and three escalating impact tests, the same bar used for hardware on commercial buildings.² SKG*** is a separate European system. It times how long a cylinder resists attack with hand tools. Three stars means at least five minutes of resistance, two minutes more than the tier below it.⁴ Neither test measures whether a lock is "bump-proof" or "unpickable." Those phrases have no fixed industry meaning. A named, published certification from an independent lab is a far more useful signal than either phrase on its own.

How long does a smart lock's battery actually last?

Less than the headline figure once you're using it daily, in some cases, but not always. Manufacturer battery ratings are typically based on a set number of unlocks per day, and a busier household can fall short of that. Independent testing on the Nuki Smart Lock Ultra in this roundup found real-world battery life landing about a month short of its own six-month claim in a busy four-person household.⁵ The SwitchBot Lock Ultra's nine-month figure, by contrast, held up in an independent review of the same lock.¹⁰ Camera-equipped locks like the E330 draw noticeably more power than a plain keypad lock, and need recharging more often as a result.⁸

Is it safe to rely on a smart lock as my only way in and out during a power or battery failure?

No lock in this roundup should be your only access method, and none of the manufacturers here design them to be. Every pick keeps a mechanical fallback: a physical key, a backup PIN, an external 9V terminal, or in the ULTRALOQ's case a full mechanical key cylinder built into the handle itself.⁶¹¹ Test that backup method once after installation, rather than assuming it works. Make sure at least one household member can operate it without the app. This matters for fire safety too. Never let a smart lock become the only way to exit a home quickly, and check that a working mechanical or thumb-turn override exists on the inside of the door, regardless of which model you choose.

Can a smart lock work alongside other smart home devices I already own?

Generally yes, though the connectivity standard matters more than the brand. Locks built around Matter, like the Nuki Ultra, or Wi-Fi with Alexa and Google Assistant support, like the eufy C220, tend to slot into an existing smart home setup with the least friction. If you're starting to build out a wider smart home around your entryway, our guide to smart plugs covers the basics of getting other devices talking to the same ecosystem.¹⁶

Do I need professional installation?

No. Every lock in this roundup is designed for a homeowner to fit with a screwdriver in well under an hour. None require rewiring or drilling beyond what the existing door hardware already has. The Nuki, in particular, is built around a sub-15-minute cylinder swap.³ If your door has non-standard hardware, an unusual thickness, or existing damage around the lock housing, a locksmith consultation before ordering is worth the modest cost. It beats returning a lock that doesn't fit.

The Best Smart Lock for You

Start with the eufy Security Smart Lock C220 if you want fast fingerprint entry, built-in Wi-Fi, and solid battery life without buying anything extra. Step up to the Nuki Smart Lock Ultra if cylinder security certification and unlock speed matter more than price. Choose the eufy Video Smart Lock E330 if seeing your door matters as much as locking it. Pick the Yale Keyless Connected lock if you'd rather skip the app entirely, the SwitchBot Lock Ultra if getting locked out worries you more than anything else, and the ULTRALOQ Latch 5 if your door takes a lever handle rather than a cylinder in the first place. If you'd rather not touch your existing cylinder at all, the Yale Linus overlays it without a permanent swap, and the WELOCK TOUCA51 brings fingerprint and card entry to a euro cylinder door at a genuinely accessible price. For a door that takes real weather on its exterior face, the Simpled SF-SPS is the most weather-sealed pick here, and for the strongest independently defined security certification in the entire lineup, the ULTRALOQ U-Bolt Pro's ANSI Grade 1 rating is hard to match.