Lockwood Fire Door Closing Systems Lockwood fire door closing systems featuring efficient ‘cam action’ technology guarantees easy access and convenience for use in normal situations as well as maximum safety in the event of fire. Lockwood 2616EMC Electromechanical Hold-Open Device for Single DoorsHold-Open Device Single Doors. Lockwood 2616CO Mechanical Coordinator for Double DoorsCoordinator for Double Doors Lockwood 2616EMCD Electromechanical Hold-Open Device for Double DoorsDouble doors. Lockwood FD480 Electromechanical Hold-Open Device for Single DoorsSingle doors. Lockwood FD481 Mechanical Coordinator for Double DoorsDouble doors. Lockwood FD484 for Double Doors with Coordinator and Electromechanical Hold-Open DeviceDouble doors.