Heath Zenith"s #79/M door chime is intended for hardwired installation, and may be used with one or two doors. It has an attractive solid oak cover with polished brass tubes, and features two distinctive chimes, one for the back door and one for the front. Powered by 16-volt AC transformer, sold separately (see Heath Zenith accessories #121AC-A and #122C-A).--Josh DettweilerWhat"s in the Box Chime, hardware kit