-- Heath Zenith's 35/M-C door chime is intended for hardwired installation, and may be used with one or two doors. It features two distinctive chimes, one for the back door and one for the front, so you'll know which door to head to. Powered by a 16-volt AC transformer, sold separately (see Heath Zenith accessories #121AC-A and #122C-A).--Josh DettweilerWhat's in the BoxChime, hardware kit Product Description Newhouse Lighting 35/M Wired Door Chime with Sleek Modern Design Cover, White From the Manufacturer The Heath Zenith 35/M features contemporary styling with a white cover in a sleek modern design. The low voltage chime has an enhanced 2-note melody for the front entrance.