Features:Easy to Install， no wiring requiredRemote control range up to 100m in open air， suitable for home， offices， hotels， etc.Build in anti-interference desgin， avoid the interference between usersInput Voltage: DC 3VChime: power by 2 x 1.5V AA battery(battery not incluced)Bell push uses 1x 12V 23A Alkaline battery (not included)Music Sound: 32 melody musicSize of Remote Control is about 72 x 38mmSize of door bell is about 95 x 60 mm 1x Remote control wireless door bell1x Remote Control