1, The doorbell must work with 2.4G WIFI of router, can't work with 5G WIFI, if your router has both 2.4G and 5G, please close the 5G firstly then connect it to the APP,after succe, you can open the 5G WiFi for normal use, thanks!! 2, The doorbell is suitable for: 40-120mm thickne of door, peephole is 15-35mm, and the cable installation length is 11cm.Not suitable to: double doors, doors with small windows or steel mesh, soft-packed doors, doors without peepholes (need to drill a peephole by yourself) View Angle and PIR Motion Detection It has 130 wide angle,when somebody pa by your door(you can set the sensitivity of the PIR to control the trigger distant) ,the camera will start recording 20 seconds video,and your phone will receive a notifiction. Alexa models(Optional) You can voice command to wake up door viewer with: alexa, show me device name ; or hey, google, show me device name. Battery Capacity and Charging Attention 2-3 months' Use with 5000mAh Battery Built-In based on 10 events per day; Battery NOT replaced. It takes at least 8~10 hours to charge,you must use 5V1A charger,do not use fast charger!!!! Please note,otherwise the battery is easily demaged.