DESCRIPTION 1-Call Audio Entrance Box Set with Handset Tenant Station Set includes DA-1DS entrance station, DA-1MD tenant station, and PT-1211C power supply Door release powered by entrance station without the need of an additional transformer Backlit directory Option button on tenant station to control an external device Call tone volume control with mute indicator 2-wire system is quick and easy to install DA-1MD Dimensions - 89mm x 200mm x 63mm (WxHxD) DA-1DS Dimensions - 100mm x 175mm x 22mm (WxHxD)