Upgrade your deadbolt with the August Wi-Fi smart lock. Remotely lock or unlock the door, check door status, grant virtual guest keys, and see who's coming and going. Or use your favorite voice assistant to control your door. Our smart lock is easy to install and attaches to your existing deadbolt on the inside of your door so you can keep your original keys. And with built-in Wi-Fi, our lock requires no additional bridge to connect. Compact, convenient, and amazingly powerful smart lock allows you to remotely lock or unlock the door, check door status, grant virtual guest keys, and see who's coming and going. Size: 1. 81"H x 2. 83"Dia. Features a compact, simple, and clean design finish to fit any home's style. Easy to install and attaches to your existing deadbolt on the inside of your door, so you can keep your original keys. With built-in Wi-Fi, the lock requires no additional bridge to connect. Requires no additional hardware to connect to Wi-Fi, so you get full voice and remote access functionality without the fuss. Includes DoorSense, a sensor that tells you when your door is open or closed. Auto-Unlock and Auto-Lock feature: recognizes when you arrive and unlocks the door, and locks the door as you leave. Control and manage your door with the August app on any iOS or Android smartphone, or use your Apple Watch to come and go. Grant guests access via app for minutes, hours, days, or more. If anything changes with the status of your door, you'll be the first to know about it thanks to the Smart Alerts feature. Uses both Bluetooth Energy (BLE) technology encryption and TLS in mobile applications. August products offer an added level of security by requiring users to verify their identity with a second form, either an e-mail or phone number. Pair with Alexa, Google Assistant, Siri, and more, to enable voice to lock, unlock, and check the status of your door. Pair with Smart Keypad for even more convenience (sold separately). Requirements: free August app for iOS or Android iOS or Android smartphone, single-cylinder deadbolt lock, and Wi-Fi Internet connection (802. 11 b/g/n 2. 4GHz). Package includes: smart lock, DoorSense sensor, two batteries, lock adapter, and mounting hardware. 1-year manufacturer limited warranty.