SENTINEL diaphragm pressure relief valves are designed to protect pumping systems from over pressure damage caused by defective equipment or a blockage in the pump system line. Robust construction ensures reliability in the rigorous service of municipal and industrial applications. Wetted materials include: PVC, CPVC, PP, PVDF, PTFE, 316 SS, A 20 and Hastelloy C. Available sizes: 1/4" - 4" depending on model.