Smart keys designed to be strong enough to protect your home;2.6 Opening methods: fingerprint, password, temporary key, IC card, mechanical key, Tuya app3. Unlock via Tuya app when the doorbell rings and view the log tracking and temporary passwords for guests4. Fits different types of doors, including wood, stainless steel, copper, double doors, and traditional security doors 5. The reversible handle adapts to installation on the left or right6. Low battery warning. A full charge once can work for about 6 months. ;, requires 4 AA batteries, the product does not include batteries)