Door bell, a wireless door bell A portable battery operated wire free door chime that can be taken around the home or outdoors as required Easy to use Free standing or wall mount Choice of 2 or 16 melodies Selectable channels to prevent external interference.Technical spec. Power supply Receiver: 4.5V(3xAA battery) Transmitter: 12V(23A type battery) Range: 100m(open air) Frequency: 433.92MHz Weight(w/o battery) Receiver: 96g Transmitter: 96g