1/2" NPT Threaded 300 PSI High CFM air compressor / tank pressure safety relief valve. Also known as a "Pop Off" or "Blow Off" valve. This relief valve is manufactured in the United States and is stamped with "UV" & "NB" symbols. The relief pressure of this valve is set at 300 PSI and is accurate within + or - 3% of the set pressure. Specifications: This valve will relieve 534 SCFM Valve Inlet Threads: 1/2" Male NPT (measure about 3/4" in diameter) Total Valve Length: 2-3/4" Installation Wrench Size: 7/8" Features a silicone rubber soft seat relief valve to prevent leaks Max temperature: 250° F Solid Brass Construction Top quality made in the U.S.A Manufactured by Conrader