The new Aqara Smart Lock U400 deadbolt uses ultra-wideband technology to unlock your door automatically as you approach, the company said at CES 2026 on Tuesday. No tapping or fumbling with your phone required. It makes Home Key use via iPhone or Apple Watch even more convenient.
“We are excited to be among the first manufacturers to deliver UWB technology in home locks to consumers,” said Cathy You, Aqara’s senior vice president of global business and strategy. “With the U400 lock, we’re redefining how consumers engage with their access control systems, providing instant, automated access without compromising privacy.”
Aqara Smart Lock U400
This keyless-entry deadbolt smart lock supports ultra-wideband (UWB) technology for hands-free use with iPhone or Apple Watch via Home Key, plus Matter over Thread networking. Also works with fingerprints, touchscreen keypad or physical key. Battery recharges via USB-C.
- Hands-free unlocking via UWB technology
- Many additional ways to unlock
- Easy USB-C charging
- Comes with installation tools
- Not cheap
- You have to install it
Aqara Smart Lock U400 is one of the first smart locks to incorporate UWB technology, used in Apple’s U1 chip found in iPhone 11 and later models. Unlike traditional Bluetooth-based smart locks, the U400 can detect your precise location and trajectory as you walk toward your door. Then it unlocks automatically when you get within a foot or two of the entrance.
How UWB technology works
The lock uses time of flight distance measurement and angle of arrival calculations to track your movement with remarkable precision. This means it can tell which side of the door you’re on and even detect the angle you approach from. That helps prevent accidental unlocks when you’re inside your home or simply passing by the door.
Users can customize the U400 to only unlock when approached from specific directions — left, right or center. That adds an extra layer of control to the hands-free experience.
Seamless Apple ecosystem integration
Photo: Aqara
U400 works with Apple’s Home Key feature in the Apple Home framework (formerly HomeKit). It automatically adds a home key to your Apple Wallet when you set up the lock in the Home app. This means your iPhone (even tucked in a bag or pocket) or Apple Watch can unlock the door as you approach. No authentication required.
For those who prefer the “traditional” method, the lock still supports tap-to-unlock using your iPhone or Apple Watch held near the hardware.
Beyond Apple Home Key, the U400 offers multiple access methods. They include fingerprint recognition, NFC cards (sold separately), one-time and recurring passcodes, voice commands through Siri or Alexa, and a traditional mechanical key for emergencies.
Built for the modern smart home
The U400 is built on the Thread protocol and is Matter-certified. That ensures compatibility with major smart home platforms, including Apple Home, Amazon Alexa, Google Home and Samsung SmartThings (no proprietary hub required). The lock integrates into existing automations and routines.
The lock features a built-in gyroscope for auto-lock functionality. It also features IP65 weather resistance for outdoor use and a rechargeable lithium-ion battery that lasts up to six months per charge. When the battery dies, you can recharge it using any USB-C power bank.
Aqara Smart Lock U400: Availability and pricing
You can buy the Aqara Smart Lock U400 through Aqara’s website, Amazon, Best Buy and select Apple Store locations for $269.99. The lock comes in black or silver.
This keyless-entry deadbolt smart lock supports ultra-wideband (UWB) technology for hands-free use with iPhone or Apple Watch via Home Key, plus Matter over Thread networking. Also works with fingerprints, touchscreen keypad or physical key. Battery recharges via USB-C.
- Hands-free unlocking via UWB technology
- Many additional ways to unlock
- Easy USB-C charging
- Comes with installation tools
- Not cheap
- You have to install it
David Snow, an expert on Apple hardware and software, writes on a variety of technological and cultural topics for Cult of Mac. They include Apple news, technology buying guides, and features about computer setups and Apple TV shows and movies.
With 30 years of experience covering technology and other subjects, he has written and edited for numerous print and online publications, including CMP Media, TechTV.com, CNET, Wired News, Red Herring magazine, Law.com, The National Law Journal and Law Technology News magazine. Among other roles, he served as executive editor of the Law.com network of websites and editorial director, technology, for ALM Media.
Snow graduated with a B.A. from Syracuse University with majors in magazine journalism and psychology. While there, he worked as a reporter for The Daily Orange newspaper and associate editor of Equal Time magazine.
Founder of the blog At the Waterline, he can be reached on X (formerly Twitter) via @atthewaterline and on Mastodon via @dsnow.
