The interesting question is what happens when the battery dies · review
Built for lettings — codes issued from a browser and a reversible handle — and the only lock here that publishes no battery life at all.
The conclusion The lettings lock on this shelf: codes issued from a web browser rather than only a phone app, remote access logs, a FOB for someone with no smartphone, and a handle set reversible for either hand. For a host with turnover those four things matter more than a grade. But it publishes no battery life of any kind — alone among eleven locks on a shelf built around that very question — no grade, no IP rating, and Wi-Fi needs an extra gateway.
NO BATTERY INFORMATION OF ANY KIND. No grade. No IP rating. No door thickness. No emergency terminal.
Alone among eleven locks, on the shelf that asks this question first.
The tag above: the interesting question is what happens when the battery dies.
No cell type. No count. No runtime. No low-battery alert. No emergency power port.
Which leaves the physical key as the entire contingency.
Eight locks here publish a figure. One publishes the assumption behind it.
Get the cell type and the expected life from the seller, and keep the key outside the house.
Which no other lock here offers.
A host with three properties and weekly turnovers is sitting at a laptop with a booking calendar open.
Generating the next guest’s code in the same window beats picking up a phone, opening an app and finding the right lock — thirty seconds against five minutes, every booking.
Sifely states codes by app or web, and access logs remotely.
A cleaner. An elderly relative. A teenager who loses phones.
No app, no code to remember, nothing to type at a door in the rain. It works like a key and can be canceled like a code.
Only this lock on the shelf has one.
Reversible, for left- and right-hand doors.
One of three locks here that includes a handle at all, and the only one that states it is reversible — another on this shelf is right-opening by default and has to be reset for the other hand.
Whatever the word says.
Without it: Bluetooth only. The app works near the door, not from away, and there is no Alexa or Google voice.
At least nine of the fifteen locks here have Wi-Fi built in with no hub.
For a let, remote code management is the whole point. Budget for the gateway and read eighty dollars as a starting figure.
On sale at around $80 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.
| Access control | Guest access codes generated instantly by app OR WEB, with remote access logs for hosts — stated, and the web half is the distinguishing feature: a host managing several properties issues codes from a browser on a laptop rather than a phone app, which no other lock on this shelf offers |
|---|---|
| Credentials | Five ways in: fingerprint, keypad, app, FOB or key. The FOB is unusual on this shelf and is the right credential for a cleaner or an elderly relative, since it needs no phone and no code to remember |
| Supplied | A complete handle set, reversible for left- and right-hand doors — stated. It is one of three locks on this shelf that includes a handle, and the only one that states it is reversible, where another is right-opening by default and needs resetting for the other hand |
| Connection | Bluetooth as standard for the app; a Sifely WiFi Gateway, sold separately, is required for unlocking from anywhere and for Alexa or Google voice control. Nine locks on this shelf have Wi-Fi built in, so the gateway is a real extra cost |
| Battery | NOT PUBLISHED. No cell type, no count, no runtime and no statement of whether cells are included — the only lock on this shelf to publish nothing at all about power, on a shelf whose own tag reads: the interesting question is what happens when the battery dies |
| Failure path | A physical key, one of the five ways in. No emergency power terminal is published — and with no battery life published either, the key is the only thing standing between the household and a locksmith |
| Fitting | Designed to fit most standard doors with no extra drilling, stated, with a few minutes to install. No door thickness range and no bore size appears |
| Grade | Not published. No BHMA grade, no IP rating and no cycle count, where four locks on this shelf publish a grade and five an ingress rating |
| Stated for | Families, kids, parents, elderly users, Airbnb and rental property — stated, and the feature set matches: codes, logs and a FOB |
| Amazon reference | B07Y5V15SY |
| EAN | 0748528493019 |
On this shelf, it is the most conspicuous omission there is: the tag above reads the interesting question is what happens when the battery dies, and this is the only one of eleven locks that does not say what the battery is. No cell type, no count, no runtime, no low-battery alert mentioned, and no emergency power terminal — which leaves the physical key as the entire contingency. Eight locks here publish a figure and one publishes the assumption behind it. Get the cell type and the expected life from the seller, and keep the key outside the house.
Because managing a let from a phone app is an irritation that compounds. A host with three properties and weekly turnovers is sitting at a laptop with a booking calendar open, and generating the next guest's code in the same window — rather than picking up a phone, opening an app and finding the right lock — is the difference between thirty seconds and five minutes, every booking. Sifely states codes can be generated by app or web and that access logs are available remotely. No other lock on this shelf mentions a web interface at all.
A purchase and a decision, and the listing is clear that it is needed: without the Sifely WiFi Gateway the lock is Bluetooth only, so the app works when you are near the door and not from away, and there is no Alexa or Google voice control. At least nine of the fifteen locks on this shelf have Wi-Fi built in with no hub. For a let, remote code management is the whole point, so the gateway is not optional in practice — budget for it and treat the eighty-dollar price as a starting figure.
Between security devices of the same category and nearby price. Shown: what they all state. A half-filled column says nothing.
| Model | Price | Credentials | Battery | Failure path | Fitting |
|---|---|---|---|---|---|
| Sifely Fingerprint smart door lock with handle and keypad | $80 | Five ways in: fingerprint, keypad, app, FOB or key. The FOB is unusual on this shelf and is the right credential for a cleaner or an elderly relative, since it needs no phone and no code to remember | NOT PUBLISHED. No cell type, no count, no runtime and no statement of whether cells are included — the only lock on this shelf to publish nothing at all about power, on a shelf whose own tag reads: the interesting question is what happens when the battery dies | A physical key, one of the five ways in. No emergency power terminal is published — and with no battery life published either, the key is the only thing standing between the household and a locksmith | Designed to fit most standard doors with no extra drilling, stated, with a few minutes to install. No door thickness range and no bore size appears |
| eufy Security T85D2 Smart Lock C34, Apple Home, keyless entry | $80 | Four ways: the app, the keypad, a physical key, and voice through Alexa or Google Assistant. There is no fingerprint reader, which is the difference from the maker's C220 on this shelf | Up to 8 months on 8 AA cells BASED ON TYPICAL USAGE OF APPROXIMATELY 10 UNLOCKS PER DAY — stated. It is the only battery figure on this shelf with its assumption published, and the assumption is what makes the figure usable: a household of five going in and out all day will see considerably less, and a second home considerably more. Every other eight-month claim here is the same arithmetic with the condition removed | A physical key, and no emergency power terminal published. One layer rather than two, where six locks on this shelf offer both — and this shelf's introduction calls this the question that should decide the purchase | Compatible with standard doors in the US and Canada, with a 15-minute installation and no drilling — stated. No bore size and no door thickness figure appears, where the maker's C220 names the 54 mm (2.13 in) bore and its spacer |
| WYZE WLCKB2 Auto-Lock Bolt v2, AI fingerprint, BHMA Grade 2 | $79 | Fingerprint, keypad code, the Wyze app over built-in Wi-Fi, a Wyze video doorbell live feed, and the physical keys. Up to 50 codes or fingerprints stored | 8 AA cells INCLUDED for up to 8 months of use, stated. Three locks on this shelf include their cells and one explicitly does not | Two published layers: eight AA cells giving up to 8 months, a USB-C port that lets any common power bank power the lock to unlock the door if the cells die, and physical backup keys as a guaranteed fallback. This shelf's introduction says the purchase should be decided on exactly this | Not published. No door thickness range and no bore size appears |
| eufy Security T8506 Smart Lock C220, fingerprint, 6 ways to unlock | $100 | Six ways: fingerprint reading in under one second, the eufy Security app, the keypad, a physical key, an Apple Watch, and Alexa or Google voice. The Apple Watch is unique on this shelf and is the most practical of the six in the rain | 8 AA cells for around 8 months, stated to vary with how often the lock is used. The variability is acknowledged without a figure, where one lock on this shelf states its assumption as about ten unlocks a day | A physical key, one of the six ways to unlock. NO emergency power terminal is published, so there is one layer rather than two — and this shelf's introduction says this is the question that should decide the purchase. Six locks on this shelf publish both a key and a USB-C port | Compatible with most standard deadbolts and fits bores under 54 mm (2.13 in) by removing a spacer — stated, with a 15-minute installation and no drilling. The spacer detail is the practical part: a smaller bore does not mean a different lock |
Details checked on October 8, 2026.
An Airbnb or a rental, where codes are issued from a laptop and the handle has to suit either hand
Amazon reports what buyers took in the month before this page was last checked: at least 1,000.
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.
