How many times have you walked up to your front door with your hands full and your “smart” lock just… doesn’t feel smart? In this video, I rip out my old lock and install the Aqara U400, because I’m chasing the unfulfilled promise of the smart home: true frictionless entry. The U400 is Aqara’s flagship, and it’s stacked—physical key, keypad, fingerprint, NFC, Apple Home Key, and (the star of the show) Ultra Wide Band. UWB is wild because it’s accurate like a mini radar: it knows which side of the door you’re on, how you’re approaching, and unlocks instantly when you actually need it. I walk through the unboxing, quick install (standard deadbolt holes), calibration, and all the unlock methods—then I connect it through Matter over Thread. I set it up on my Apple TV 4K Thread border router first, then bring it into Home Assistant (my smart home platform of choice) so I can build fast, local automations like auto-locking when the alarm arms or unlocking based on arrival. My final take: this lock is a beast and feels futureproof, but Matter is still maturing—so some advanced stuff (like fingerprint management) still lives in the Aqara app.