Smart home company Aqara today debuted its latest smart lock, the U400. The Aqara Smart Lock U400 incorporates ultra wideband (UWB) technology for more precise location-based tracking and automated door unlocking.
There are few UWB smart locks on the market, but the technology uses the UWB chip in the iPhone to unlock the door right as you approach. There is no need to tap an iPhone on the lock with UWB, so the door can be unlocked entirely hands-free. We were able to test the lock ahead of its introduction at CES, and the UWB technology worked as advertised.
Walking up to the U400 with iPhone tucked in a pocket triggered the lock to unlock, but only within a foot or two of the door. It's sensitive enough that Aqara added a customization option to allow the U400 only to unlock when approached from a set angle of arrival, such as left, right, or center. Setting a specific direction can avoid accidental unlocks when you're near the door, and UWB is sensitive enough to know what side of the door a person is on.
The U400 works with the Apple Home Key feature, so it can also be unlocked via a card stored in the Wallet app. Home Key can be customized to unlock a door by holding your iPhone or Apple Watch near the lock, but UWB simplifies the process further and makes it more precise. There is no need for a PIN, tap, or authentication with the U400, and the iPhone or Apple Watch doesn't need to be explicitly tapped on the lock.
Like prior Aqara locks, the U400 offers a wide range of options for access. It supports unlocking with a fingerprint through a fingerprint sensor, NFC, an included key, or an access code with the included keypad. One-time and time-specific codes can be given to guests, and the lock can be set to lock automatically after user-specified period of time. Since the lock can be unlocked automatically if you're near it, turning on the auto-lock ensures that it doesn't stay unlocked if it's activated accidentally.
If you want to leave a door unlocked for a period of time or permanently, there is a dedicated Passage mode that can be set.
Since it is Matter and Thread enabled, the U400 can be connected to HomeKit and accessed through the Home app. It can be used in automations alongside other smart home devices, and the lock can be controlled with Siri voice commands. It also works with the Aqara app, and can be connected to an Aqara hub. Since it supports Matter, an Aqara hub is not required for full functionality, but a Thread Border Router and Matter hub are needed. The Apple TV 4K and HomePod mini work as home hubs for the Apple ecosystem.
Aqara says the U400 supports Aliro, so it is able to be unlocked with a smartphone regardless of operating system. It is also more secure than Bluetooth, because it uses time-of-flight signals instead of simply signal strength for unlocking, so there is no option for a relay attack.
The U400 is powered by a 4,880 mAh battery that can be removed from the lock and charged via USB-C, and it is supposed to last for up to six months per charge. Several Aqara locks used replaceable batteries, so the rechargeable battery is a nice upgrade. Exterior components have IP65 water and dust resistance for outdoor use.
Aqara is offering the U400 in Silver and Black. It is designed to replace a standard deadbolt, and it includes all of the necessary hardware for a swap.
More information on the U400 can be found on Aqara's website.
Article Link: CES 2026: Aqara Launches U400 Smart Lock With HomeKit and Hands-Free UWB Unlocking
