certified 1/4" NPT 165 PSI Industrial 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 165 PSI and is accurate within + or - 3% of the set pressure. Specifications: This valve will relieve 145 SCFM Valve Inlet Threads: 1/4" Male NPT (Measure about 1/2" in diameter) Total Valve Length: 1-3/4" Installation Wrench Size: 11/16" Features a Silicone Rubber Soft Seat Relief Valve to Prevent Leaks Max Temperature: 250° F Solid Brass Construction Made in the USA