The interesting question is what happens when the battery dies · review
SwitchBot states a next-generation motor, a full metal housing half as thick as its predecessor, up to eighteen unlocking methods with the Matter hub and touchscreen keypad, and a rechargeable main battery quoted at up to nine months.
The bottom line The best-made retrofit body here, in a system that is priced by the piece. Add up the hub and keypad before comparing.
Retrofit locks are usually judged on features. This one is worth judging on its shape.
A retrofit lock sits on the inside face of the door, over the thumbturn. That space is often occupied — by a chain, a letterbox flap, a handle, or by the door simply not having enough stile to spare. SwitchBot states a full metal housing half the thickness of the previous generation, and on a narrow door that is the difference between fitting and returning it.
The figure includes every combination available once the Matter hub and the touchscreen keypad are added, both of which are separate purchases. In daily use a household picks one method and one fallback. Price the whole set before comparing it with a lock that includes its keypad.
Up to nine months on a rechargeable main battery, stated without the daily cycle count that figure assumes. The fallback is the one that matters: this is a retrofit, so the original cylinder and key still open the door when everything electronic has stopped.
A door with awkward clearance, and an owner who will actually use more than one unlocking method.
On sale from 180 € to 250 € on the German, French, Italian and Spanish Amazon stores at the time of checking.
Listed but with no offer on the British Amazon store — the reference exists there and nobody is currently selling it.
Not found on the American Amazon store, where the buy link falls back to a local search rather than to a page that does not exist.
Prices and availability are what Keepa reported on the date this page was updated; both move.
Prices quoted in this text were read on 2 September 2026. The live price is at the top of the page.
| Type | Retrofit — mounts over the existing thumbturn |
|---|---|
| Body | Full metal, 50% slimmer than the previous generation, stated by SwitchBot |
| Access | Up to 18 methods with Matter hub and touchscreen keypad |
| Power | Rechargeable main battery, up to 9 months stated |
| Alerts | Real-time door and lock status, unlocked-door warnings |
| Locking | Magnetic automatic locking |
| Amazon reference | B0F2HLJCDR (same reference on 5 Amazon marketplaces) |
| EAN | 0810150544176 |
Two or three are. The number is a marketing count of every combination — app, keypad, fingerprint, card, voice, geofence and so on — and most households settle on one everyday method and one fallback. What matters is that the fallback works when the network is down and the phone is flat, which on any retrofit lock means the original key.
On some doors, yes. Retrofit locks sit proud of the inside face and can foul a door chain, a letterbox flap or a handle. A housing half the thickness is the difference between fitting and not fitting on a narrow stile.
The Matter hub and the touchscreen keypad, both of which the extended unlock methods depend on. Price the combination rather than the lock, and compare that against the locks in this hub with the features built in.
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.
≈ £200 / 170 €
Retrofit · built-in Wi-Fi, no bridge · Matter · 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.
≈ £189 / 233 €
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 flat where nothing may be altered.
≈ 130 €
