The Super-Chek design has been proven over the last 15 years to be the standard for air compressor in-tank check valves. One-piece brass bodies, stainless steel springs, and glass-filled fluoropolymer poppets all add up to long term reliability, while the eight discharge holes insure quiet operation. Valves may be disassembled for cleaning or repair. Valves are 100% tested for backflow leakage performance. 450 PSI max pressure, 400 deg. F max temperature.