Valves with connections of 1/4" or 1/2" have a diaphragm made of Viton<reg> and withstand a maximum inlet pressure of 210 psig. All other valves have a PTFE shaft design and withstand a maximum inlet pressure of 140 psig. The shaft design prevents emergency shutdown with a three-seal system that will vent liquid to warn of approaching maintenance. All valves are recommended for liquid applications.