The Pipe O-ring check valves offer optimized directional flow regulation and bubble shut off specifically for liquids and gasses. Not used as relief devices, these check valves possess an opening pressure of 1.5 bar. The body, cover, poppet and other parts are all fabricated from 316 stainless steel. The spring is made out of 300 series stainless steel while its O-ring is made out of Viton A.