The Catalog 177 and 178 mortise type door openers are dependable long service devices, providing the security and convenience of remote control door-lock operation. These units flush mount in place of the regular door strike plate and are ideal for narrow door stiles. With the non-reverse acting units, the door remains locked until the opener is electrically actuated by a remote contact device. For reverse acting units, the door remains unlocked (with current off). When energized through a timer or manual switch, the unit keeps the door locked. For AC operation, use with either an 88-50, 596, or 592 Transformer. For use in apartments, offices, banks, industrial buildings, schools, and institutions. Use in door interlocking and control systems