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:85×67×28(mm) button(transmitter)size:86×43×18(mm) power source of receiver: 2 × aabattery/ac230v/ac110v approval:ce,r&tte,rohs