Abstract: An apparatus is provided for securing together two members which are slidable towards and away from each other to provide a respective open and closed (locked) mode, wherein a plurality of devices are adapted to secure the members in a closed mode, and a control unit is adapted to operate the devices. The devices are in the embodiments described spaced longitudinally apart along a vertical edge or stile of a closure member, which may be a patio door, window, or other closure, with the control unit being disposed intermediate the devices and being operatively linked thereto by a connecting device for actuating the devices. The control unit may be driven manually by a control handle, by a solenoid, by an electric or electro-mechanical motor device, or by spring-loaded interlocking devices. The devices cooperate with keeper devices for securing the closure members together in the closed (locked) mode.