Note: Product visuals are presented for illustrative purposes only and may vary slightly in colour, finish, proportions, and final installed appearance. For the most realistic representation, please refer to our Customer Gallery featuring actual installation photos.
Truly Hands-Free Entry with UWB
The Aqara U400 unlocks automatically as you approach — genuinely hands-free, not just tap-to-unlock — using Ultra-Wideband (UWB) technology with supported iPhone and Apple Watch models. It's built around a real BHMA-certified deadbolt, not a smart add-on bolted to a lighter-duty mechanism, which matters if you want the convenience of a hands-free lock without giving up the physical security of a proper deadbolt.
Why UWB Instead of Bluetooth
Bluetooth-based hands-free locks struggle to tell how far away your phone actually is — Bluetooth signal strength is a rough proxy for distance at best, which can cause accidental unlocks when you're simply walking past the house, or leave the lock vulnerable to relay attacks where someone amplifies the signal from a distance. UWB is a fundamentally different radio technology that measures both direction and distance precisely, in centimetres rather than a rough signal-strength guess, so the lock only engages when you're genuinely approaching the door with an authorised device in hand.
Ways to Unlock
Beyond UWB hands-free entry: Apple Home Key (tap to unlock), fingerprint (stores up to 50), keypad PIN codes (including one-time and scheduled codes for guests, cleaners or Airbnb stays), NFC cards or tags, app control, and a physical key override for the times you'd simply rather use a key.
Real Deadbolt Hardware
The U400 replaces a traditional deadbolt with BHMA-certified hardware — the same physical security standard used to grade conventional mechanical deadbolts on resistance to prying, drilling and forced entry — so you're getting genuine intrusion resistance, not just smart features layered onto a weaker mechanism underneath.
Smart Home Integration
Matter over Thread support means the U400 works natively with Apple Home, Alexa, Google Home, SmartThings and Home Assistant, and it can link with Aqara cameras and hubs to trigger lights or scenes whenever the door unlocks — arriving home can mean the porch light, the air-con and the security camera's "home" mode all activate together, without you touching anything else.
Weatherproofing & Power
The exterior unit is IP65-rated for outdoor doors and gates, powered by a rechargeable battery with USB-C emergency charging as backup if it ever runs flat.
Real installation photos from our customers.
| Model / Kit Variants | Online Smart Lock U400 |
|---|---|
| Lock Type | American Standard Deadbolt, 60-70mm backset; SC1 5-pin cylinder with rekey support; single deadbolt tongue |
| Unlocking Methods | UWB hands-free unlock (iOS only), Apple Home Key, Fingerprint, Password (incl. periodic and one-time), NFC, Bluetooth app unlock, Mechanical Key, Remote Aqara unlock, Matter password, Automation unlocking, Voice unlocking (ecosystem-dependent) |
| Connectivity | UWB (Aliro standard, ~10m range), Bluetooth 5.2 (~35m open space), Thread/Matter 1.4 (~20m indoor); a Thread-enabled Matter Controller (e.g. Aqara Hub) must be bound for remote unlock, automation, and voice control |
| Power Source | Lithium-ion battery, 4880mAh / 35.6Wh, 7.3V; Type-C emergency power supply, 5V DC |
| Battery Life | Up to 6 months |
| Warranty | 2 Year Parts and On-Site Warranty; 6-month battery warranty. Other accessories not included. |
| Dimensions | Front lock: 167 x 76 x 25.5mm; Rear lock: 178 x 76 x 46.9mm |
| Color | Local version: Black, Silver (matte spray coating) |
| Operating Temperature | Front lock: -35C ~ 66C; Rear lock: -18C ~ 55C |
| Charging Temperature | 0C ~ 40C |
| Operating Humidity | 0 ~ 93% RH, non-condensing |
| IP Rating | IP65 (front lock only; rear lock is not waterproof) |
| Electrostatic Protection | Contact: 8KV, Non-contact: 15KV |
| Voice Language | English (default), French; OTA update adds Spanish and other languages |
| Fingerprint Sensor | Response time <0.5s, capacity 50 fingerprints, false acceptance rate <1 in a million, false rejection rate <1 in 100,000 |
| NFC Capacity | Up to 25 units, 13.56MHz, identification distance <=3cm |
| Password Capacity | 75 sets total (includes periodic passwords; up to 8 one-time passwords per hour), 50 users |
| Third-Party Platform Support | Aqara Home and Apple Home give the full feature set (UWB unlock, app remote lock/unlock, voice control, automation). Google Home, Amazon Alexa, Samsung SmartThings, Home Assistant, and Homey support remote unlock and automation via Matter, but not UWB or native voice control. All remote functions require a Thread-enabled Matter Controller (e.g. an Aqara Hub) to be bound first |
| What is in the Box | Rechargeable Li-ion Battery x1 , 1x Aqara Hub M100 included |
Frequently Asked Questions
Have questions? We're here to help you.
Yes. The Aqara U400 is a smart deadbolt designed to replace a standard single-cylinder deadbolt on many residential doors, while keeping the lower latch if present.
UWB (Ultra-Wideband) is a short-range wireless technology that measures distance and direction with much higher accuracy than Bluetooth. This allows the U400 to better detect your true approach to the door and helps reduce accidental or relay-based unlocks.
Yes. The U400 is Matter-certified and built on Thread, allowing it to work with Apple Home, Alexa, Google Home, SmartThings, Home Assistant and other supported platforms via compatible controllers.
The U400 fits many wooden doors that use a standard North American-style deadbolt, which can include apartments, condos and landed homes. Always verify door thickness, backset and bore size against the installation guide before purchase.
UWB uses precise timing and direction sensing with scrambled timestamps, making it more resistant to relay and replay attacks than typical Bluetooth proximity systems. The lock also uses BHMA-certified deadbolt hardware and supports features like failed-attempt lockout.
Yes. With support for Matter over Thread and being described as Aliro-ready, the U400 is designed for long-term interoperability across smart-home ecosystems and future platform updates.
The U400 provides low-battery alerts via the app and voice notifications. It can be recharged using its USB-C port, powered temporarily via USB-C if fully depleted, or unlocked using the included mechanical key.