Potter PTS-C is designed to supervise sprinkler system control valves and may also be used to secure gates and other applications. This unit is particularly useful for unusual conditions, such as non-rising stem valves. Nema 6P enclosure allows the device to be mounted outdoors, even in areas subject to fl ooding such as pits and wells. Sealed reed switch operation virtually eliminates contact corrosion. Turning the valve wheel will pull the plug out of the receptacle. The plug cannot be reinserted after operation until the plug receptacle cover is removed with the special hex key provided. This key should be left with the building owner or responsible party. Replacement or additional cover tamper screws and hex keys are available