Edwards Signaling Catalog Number 188 mortise type door opener is a dependable long service device, providing the security and convenience of remote control door-lock operation. The door remains locked until the opener is electrically actuated by a contact device. For AC operation, use with an 88-50, 596 or 598 Transformer. For use in apartments, offices, banks, industrial buildings, schools, and institutions. Use in door interlocking and control systems with timed or manual operation.