The INGERSOLL RAND MLK-117A is a valve chest cover gasket used in MLK and HLK Series air chain hoists. It seals the joint between the valve chest and its cover plate, keeping air pressure inside the valve circuit so the up and down valves actuate cleanly. Air escaping past a worn gasket at this point shows up as weak or delayed response on the pendant, and the gasket is normally replaced whenever the valve chest is opened for spring or actuator service.