* Our Door Chimes is famous for their high quality clear and sweet electro-mechanical “Ding Dong” sound with most application in hotel rooms and residential buildings, apartments and houses. * AC (Built-in Transformer) operated or DC (Battery) operated for selection. ( AC : VZ13-20AC & VZ14-20AC / DC : VZ13-20 & VZ14-20 ) * Simple but Elegant design to maintain the perfect harmony of interior design. * Push button and woodscrews are included.