wireless doorbells and door chimes with one piece ofmusic:ding…dong… or customize different types of music transmissionrange: 100m (in open area) power source of button: 1×23a 12vbattery (included) transmitting frequency: 433mhz/315mhz/418mhzreceiver(bell) size：110×75×23(mm) button(transmitter)size：86×43×18(mm) power source of receiver: 3 × aabattery/ac130v/ac110v