Mircom apartment intercom station 5 wire, white, horizontal mount. 3 Button IS-401B 4 Wire - Horizontal Mounting IS-81MV 4 Wire - Vertical Mounting MIRCOM Intercom Station Used with Mircom "G" Series or M-3000 Lobby Panels. Use with 1B-2A Backbox Push-buttons: 3 Momentary Speaker: 45 ohm 3.5" Speaker Wiring: 3 Common, 1 Selective Amplifier: MA-485A Dimensions: 8 1/16" W X 5 5/16" H