1.This product is suitable for home,hotel ,hospital ect 2.Sound category :Single dingdong,Double dingdong,west minister, 12 melodies, and others. 3.Sender:DC12V 23A battery 1piece 4.Receiver:DC3V(1.5V AA*2) 5.Frepuency:433.92MHz 6.Remote control distance >=30m 7.Receiver use digital codes 8.One sender can control one or more receivers