Plug through wireless doorbell A plug-in mains operated wire free door chime with integral 13A socket Easy to install Choice of 16 melodies Digital coded signal to prevent outside interference Indoor use only Technical spec. Power supply Receiver: 230VAC, 50Hz. Transmitter: 12V(23A type battery) Range: 80m(open air) Frequency: 433.92MHz Weight(w/o battery) Receiver: 129g Transmitter: 25g