Name: Aqara Smart Lock U400
Brand: Aqara

Key specs

Bluetooth: Yes

Price & availability

Where to buy

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Buying decision

Should you buy it?

Buy the U400 if you want hands-free unlocking with an iPhone: reviewers praised its ultra-wideband unlocking that works well, many unlock methods, Matter over Thread support and wide platform compatibility. Skip it if you don't have a Thread controller, because it lacks Wi-Fi and needs a Thread-enabled Matter hub. It's a little bulky and expensive, battery life could be better, and NFC cards aren't included.

Best for

Smart homes with a Thread hub that want hands-free entry.

Not for

Homes without a Thread controller.

Main strengthHands-free UWB unlocking

Main weaknessNeeds a Thread hub

Reasons to buy

Hands-free UWB unlocking

Many unlock methods

Matter over Thread

Broad platform support

Reasons to avoid

Needs a Thread hub

Bulky

Expensive

Measured view8.3/10What the pros say · verified oct 8, 2026.

ScoreVerified Oct 8, 2026

Same category

Alternatives worth a look

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AqaraSmart Lock U600Model EL-D11E; slim lever lock for UK multipoint doors, 40-80mm door thickness; 4x AA + USB-C emergency power

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Product data

Full specifications

51 attributes, grouped for quick scanning. Verified Oct 8, 2026. Spot a wrong value? Hit the next to it.

Face recognition: No

Bluetooth Compatibility: Bluetooth 5.0

Low Battery Alert: Yes
Battery Type: Built-in
Battery Life: 6 months
Backup Battery: USB-C Emergency Port

Remote: Yes
Nfc Tag: Yes
Matter Support: Yes
5 GHz Wi-Fi: No
2.4 GHz Wi-Fi: No
Connections: Bluetooth, Matter over Thread, Wireless

Tamper Proof Alert: Yes

Physical Key: Yes
Periodic Password: Yes
Passcode: Yes
Other: Yes
One Time Password: Yes
Fingerprint: Yes
Emergency Fingerprint: No
Doorbell: No
Door Lock Unlock: Yes
Customizable Area: No
Away: No
Anti Peep Password: Yes
After Door Closed: Yes

Batteries: Rechargeable lithium-ion
Internet Access: Some features require internet access
Other Features: Batteries Required, Bluetooth, Charging, HomeKit Compatible, Thread, Waterproof, Wireless
Cable Length: 3.9 in. / 10 cm
Length: 4.2 in. / 10.7 cm
Cable type: Dock to USB Cable

Storage: No
Bluetooth Version: Yes
Release Year: 2026
Release Date: 2026-01-07

Width: 34 oz. / 967 g (without battery), 40 oz. / 1140 g (with battery)

Zigbee: No
Z Wave: No
Thread: Thread Border Router required
Home Assistant: Yes
Apple Home Key: Yes
Apple Home: Yes

Microsd Slot: No

Works With Smartthings: Yes
Night Vision: No
Motion Detection: No
Works With Google Home: Yes
Works With Alexa: Yes

HD video: No
2K video: No

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Community says

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Smart Lock U400

Where to buy

Should you buy it?

How it stacks up

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Full specifications

Community says