The interesting question is what happens when the battery dies · review
A retrofit that leaves your door, your cylinder and your key exactly as they are — and, unlike most locks here, it will not fit a standard American deadbolt.
The conclusion A retrofit, like four other locks on this shelf, and the distinction matters more than the price: it turns your existing thumbturn, so the cylinder, the door and above all the original key are untouched — which answers the hub's battery question by never asking it. Matter support adds an open standard. Read the first bullet before anything else: euro profile only, explicitly not compatible with a US deadbolt, and at three hundred and fifty-nine dollars it adds no mechanical security at all.
No battery life. No BHMA or EN grade. No IP rating. No keypad. No fingerprint.
Because it decides everything on an American door.
Euro profile cylinders only. Not compatible with standard US deadbolt locks, in Nuki’s own words.
A euro cylinder is a flat figure-of-eight barrel held by one screw through the lock case — standard across Europe. An American front door normally carries a round deadbolt with a thumbturn.
Replacement door, apartment, property abroad: this is the lock. Ordinary US deadbolt: it is not a candidate.
Which is how it answers the shelf’s central question.
This shelf’s introduction: the purchase should be decided by what happens at zero battery — a key override, an emergency terminal, or nothing at all.
A retrofit sidesteps it. The cylinder outside the door is the one that was always there, so the original key works whatever the motor inside is doing.
That is worth more than any emergency port.
It also means this adds convenience and no mechanical security. The cylinder is exactly as snappable as it was yesterday.
And it is part of what the money buys.
Matter is an open standard supported by Apple, Google, Amazon and SmartThings together. A Matter lock works with the hub you own now and the one you own in five years, and it works locally rather than only through the maker’s cloud.
Apart from the Aqara U200 and the Nuki Smart Lock Pro, the locks on this shelf list Alexa and Google compatibility — proprietary integrations that exist at the manufacturer’s discretion.
No keypad, no fingerprint reader, no visible change.
Which is the point for a listed building, a rented apartment or a door you are not allowed to alter.
It also means a dead phone leaves you with the key, and nothing else.
On sale at around $359 on the American Amazon store at the time of checking.
Prices and availability are what Keepa reported on the date this page was updated; both move.
Prices quoted in this text were read on October 8, 2026. The live price is at the top of the page.
| Type | A RETROFIT lock, one of five on this shelf alongside the Aqara U200, the Nuki Smart Lock Pro, the SwitchBot Lock Ultra and the Signstek. This shelf's introduction draws the distinction first: a retrofit sits on the inside of your existing door and turns the thumbturn you already have, so the cylinder, the key and the door are unchanged. The remaining ten locks here replace the lock hardware itself |
|---|---|
| Compatibility | Euro profile cylinders only, and NOT compatible with standard US deadbolt locks — stated in the first bullet, with international and European-style doors named. On an American shelf that is the fact that decides everything, and Nuki states it before anything else |
| Failure path | By construction: the original cylinder and key are untouched, so the key opens the door from outside whatever the lock's battery is doing. That is the quiet advantage of a retrofit and it is why this shelf's introduction separates the two kinds. No emergency power terminal is published and no battery life appears |
| Supplied | A Universal Cylinder is included, stated, fitted alongside the lock in under 15 minutes with no drilling, no extra tools and a visual step-by-step guide in the app |
| Connection | Built-in 2.4 GHz Wi-Fi with no extra hub, plus Bluetooth and Matter — stated. The Aqara U200 and the Nuki Smart Lock Pro name Matter too; it means the lock is not tied to a single ecosystem's future |
| Credentials | The app, auto-unlock on arrival, remote lock and unlock, access permission management, and voice through Apple Home, Google Assistant, Alexa or SmartThings. No keypad and no fingerprint reader: there is nothing outside the door |
| Battery | Not published. No cell type, no capacity and no runtime appears, where at least eight of the fifteen locks on this shelf publish a figure. On a retrofit the consequence is milder, because the key still works |
| Security | No BHMA grade, no EN grade and no IP rating published. A retrofit does not change the door's security: the cylinder is whatever was already fitted, which cuts both ways |
| Price | Three hundred and fifty-nine dollars, the highest published price on this shelf by nearly a hundred dollars |
| Amazon reference | B0GQ4KD8C5 |
| EAN | 9120072084676 |
Almost certainly not, and Nuki says so in its first bullet: the Ultra is designed for euro profile cylinders and is not compatible with standard US deadbolt locks. A euro cylinder is a flat figure-of-eight barrel held by one screw through the lock case, standard across Europe; an American front door normally carries a round deadbolt with a thumbturn. If your door has a euro cylinder — a replacement door, an apartment, a property abroad — this is the lock. If it has a deadbolt, this one is not a candidate: look at the other locks on this shelf, and check each listing for the doors it states it fits.
Because it never takes the key away. This shelf's introduction says the purchase should be decided by what happens at zero battery — a key override, an emergency terminal, or nothing — and a retrofit sidesteps the whole question: the cylinder outside the door is the one that was always there, so the original key works regardless of what the motor inside is doing. That is worth more than any emergency terminal. What it also means is that the lock adds convenience and no mechanical security: the cylinder is exactly as snappable as it was before.
Independence from one company's roadmap. Matter is an open smart-home standard supported by Apple, Google, Amazon and SmartThings together, so a Matter lock works with whichever hub you own now and whichever you own in five years — and it works locally rather than only through the maker's cloud. On this shelf the Aqara U200 and the Nuki Smart Lock Pro name it as well; most of the others list only Alexa and Google compatibility, which are proprietary integrations that exist at the manufacturer's discretion. At three hundred and fifty-nine dollars that longevity is part of what is being bought.
Between security devices of the same category and nearby price. Shown: what they all state. A half-filled column says nothing.
| Model | Price | Failure path | Credentials | Battery |
|---|---|---|---|---|
| Nuki 221272 Smart Lock Ultra, euro profile retrofit, with Universal Cylinder | $359 | By construction: the original cylinder and key are untouched, so the key opens the door from outside whatever the lock's battery is doing. That is the quiet advantage of a retrofit and it is why this shelf's introduction separates the two kinds. No emergency power terminal is published and no battery life appears | The app, auto-unlock on arrival, remote lock and unlock, access permission management, and voice through Apple Home, Google Assistant, Alexa or SmartThings. No keypad and no fingerprint reader: there is nothing outside the door | Not published. No cell type, no capacity and no runtime appears, where at least eight of the fifteen locks on this shelf publish a figure. On a retrofit the consequence is milder, because the key still works |
| YINTIN X5 3D face recognition smart lock with camera, palm vein and 4-inch indoor screen | $259 | Both layers: a mechanical key and a USB-C emergency power input, with low-battery alerts before either is needed. The battery is rechargeable and no runtime figure is published | Eight ways in, named: 3D face recognition, palm vein, fingerprint, passcode, key card, app, mechanical key and remote unlock. It is the widest credential set on this shelf | Rechargeable with low-battery alerts, stated. NO runtime figure appears, where at least eight of the fifteen locks on this shelf publish one |
| We Technology RL14 3D face recognition smart lock with camera and intercom | $200 | Both layers: a mechanical key among the seven unlocking methods, and USB Type-C emergency power. On a lock needing recharging every three to four months, the emergency port is not a last resort but a routine part of ownership | Seven ways in: face recognition, fingerprint, passcode, IC card, mechanical key, the Tuya app and a temporary password. Up to 100 total users, with fingerprint and card capacities stated to be in the specifications rather than on the page | A 4200 mAh lithium battery giving approximately 3–4 months, with USB Type-C emergency power — stated. Three to four months is the SHORTEST runtime on this shelf, where the longest is a year and most are six to eight months. A face reader that wakes at 5–20 cm (2 to 7.9 in) is expensive to keep awake |
| Philips DDL242X-1HW-L 4200 Series Wi-Fi keypad deadbolt with handle set | $170 | NOT PUBLISHED. Ten bullets, one of them devoted entirely to the battery and its prohibitions, and not one word about a physical key or an emergency power terminal. This shelf's tag reads: the interesting question is what happens when the battery dies. This shelf's introduction says the answer is a key override, an emergency terminal that takes a power bank, or nothing at all — and at least ten of the fifteen locks here answer it | Keypad codes — permanent, one-time, periodic and recurring — plus fingerprints unlocking in 0.3 seconds, the app, and Alexa or Google voice. Four code types is the most flexible code scheme on this shelf | Up to 6 months with an intelligent low-battery alert — stated, with two conditions: BATTERIES ARE NOT INCLUDED, and only standard 1.5 V alkaline cells may be used, with rechargeable and high-power lithium cells explicitly forbidden to prevent damage. That prohibition is unique on this shelf and it narrows the options at replacement time |
Details checked on October 8, 2026.
A euro-profile door — a European property, an apartment, an Airbnb abroad — where the existing key must keep working
Amazon reports what buyers took in the month before this page was last checked: at least 50.
The figure is a floor, rounded by Amazon, and read through Keepa — it says what buyers picked, not what a maker claims.
Specifications: the manufacturer sheet for home security products and the matching Amazon product page. Prices and availability: Keepa. Every figure on this page names its source.
Matter over Thread · Apple Home Key · rechargeable Li-ion, 6 months stated · no drilling
A retrofit lock with native Matter over Thread, so it joins Apple Home, Google Home and Alexa without a vendor bridge. Aqara states Apple Home Key support, a rechargeable battery quoted at up to six months, and a quiet unlocking mode.
Best for: A household already running Matter or Apple Home, that wants the lock to be part of it rather than another app.
Retrofit · built-in Wi-Fi, no bridge · Matter over Thread · charged at the door · months per charge
Nuki's fifth-generation lock puts Wi-Fi inside the unit, so remote access needs no bridge or hub, and adds Matter alongside Bluetooth. The battery charges at the door with the supplied cable rather than coming off it.
Best for: A household that wants remote access without adding another box to the hallway.
Retrofit · fingerprint, app and Bluetooth · magnetic auto-lock · 6 cells · no drilling
A retrofit lock that mounts over an existing cylinder with no drilling and no cylinder change. Signstek states fingerprint, app and Bluetooth access, magnetic auto-locking, and six batteries; the existing key still works from outside.
Best for: A first smart lock, and particularly a rented apartment where nothing may be altered.
