Praher Plastics 150-CLP 1-1/2" Knife Gate Valve. This Safety Clip is designed to fit 1.5" - 2.5" Knife Gate Valves and ensures the valve remains open. The Praher Plastics Knife Gate Valve is designed to quickly slice into matter in order to quickly shut off the flow. Simple to use with maintenance free operation and a safety close system. Trust Praher Plastics for all your pool and spa equipment needs.