Powered by Ultra-Wideband (UWB), the Smart Lock U400 unlocks as you approach with your iPhone or Apple Watch. a hands-free, privacy preserving entry with no codes and no biometric checks.
Note: UWB requires a Thread-enabled Apple Home hub(HomePod 2, HomePod mini, Apple TV 4K 2021/2022) and is supported on Apple Watch Series 6+ (excl. SE) running watchOS 11.5+ and iPhone 11+ (excl. iPhone SE & 16e) running iOS 18.5+. For the smoothest UWB experience, iOS 26.2 or later is recommended.
Based on range and angle measurements, UWB detects your exact position to determine your unlock intention. It unlocks precisely when you're ready to enter and avoids any accidental or delayed openings. Even if you walk by or stand near the entrance, it stays locked until you approach head-on with the intention to enter, preventing accidental unlocks and delivering a truly secure, hands-free experience.
Unlike fingerprint or facial recognition, UWB unlocking doesn’t require collecting or storing your biometric data. There’s no scanning, no waiting, and nothing to fail when conditions aren’t perfect.
Rain-soaked hands, gloves on, or a hat, mask, and scarf covering your face — UWB still works smoothly. As you approach, the door unlocks instantly and securely, letting you walk in without pausing or adjusting how you arrive home.
Just a seamless, private, and reliable way to enter — every time.
Whether your hands are full of groceries, you're carrying your child, or returning home with packages after a long day, UWB senses your approach and unlocks automatically. No need to take out your phone. No need to tap a fingerprint. Even with gloves on, wet hands in the rain, or when you simply want a smoother arrival, you can enter effortlessly and securely. Just walk up. The lock takes care of the rest.
No more fingerprint enrollment or complicated setups. Easily share UWB access with family members so they can walk up and unlock the door just like you. Effortless, secure, and truly smart.
Simply add the Apple Home Key to your Wallet and unlock the door with your iPhone or Apple Watch, even when the devices are powered off. You can also easily share the home key with family members or provide guest codes to visitors,ensuring both security and convenience.
The Smart Lock U400 also features a built-in ergonomic fingerprint reader, which can securely store up to 50 fingerprints for quick touch-to open access. The lock offers a highly accurate recognition rate of up to 98.6%.
Ask Siri or Alexa to open the door when your hands are full with groceries, kids, or on rainy days.
Please note: Voice unlocking is only available in Apple Home and Amazon Alexa ecosystems.
Share a passcode that’s valid only during the timeframe you set, ideal for housekeepers, caregivers, and short-term guests.
Generate up to 8 passcodes per hour, even when the lock is offline, and issue them remotely to visitors, deliveries, or service providers.
Note: One-time passwords can only be obtained via the Aqara Home app.
You can also unlock with a keypad passcode, remotely via the app (requires a Thread-enabled Matter controller), a physical key, or an NFC card (Aqara NFC cards sold separately)
Flexible and versatile smart home security.
Our smart lock is equipped with rechargeable batteries that only requires a few hours to fully charge, and it can last up to 6 months on a single charge. Through the interior USB-C port, you can recharge the device with a powerbank anytime, removing battery anxiety for good.
When the battery level drops to 20%, you'll receive a low battery notification, giving you plenty of time to recharge before running out.
In case you forget to recharge, the U400 lock features an exterior USB-C Emergency Charging Port, allowing you to power up with a power bank or a phone that supports USB-C to USB-C charging.
Note: The USB-C port on the outer panel is for emergency unlock only, not normal charging.
Can I use UWB and Home Key without a hub? Which Apple devices are required for UWB access?
No. Requires a Thread-enabled Apple hub (HomePod 2 / mini, Apple TV 4K 2021/2022) and supported devices: Apple Watch Series 6+ (excl. SE) on watchOS 11.5+ and iPhone 11+ (excl. SE & 16e) on iOS 18.5+. iOS 26.2 recommended for the best UWB experience.
Why can't my U400 pair with the app (non-Aqara app)?
Check the following: • Use a Matter-over-Thread hub; • Enable IPv6 on your Wi-Fi; • Phone and hub on the same Wi-Fi; • Bluetooth turned on; • Lock within 5 m of the hub with no obstruction; • Press the Set button before pairing;
Why is there no response or failed binding when using the Matter pairing code?
The lock’s Matter code only works for the first binding. To connect to another ecosystem, generate a new pairing code from the connected ecosystem. If it still doesn’t work, reset the lock to reactivate the original code.
If I don’t have a compatible hub, can I still use the lock?
Yes. You can still use the basic features via Bluetooth in the Aqara app (like adding fingerprints, passcodes, and Auto Lock). However, features such as UWB, Home Key, remote unlocking, and automations will not be available.
Why is the Aqara U400 failing to unlock with my fingerprint?
Ensure your finger and the sensor are clean and dry; wipe both with a clean cloth. Some fingerprints (e.g., children or elderly) may be too faint to recognize. Try another person to check if it’s a fingerprint or device issue.