DN 5.3 mm (7/32"). Flow capacity of 900 l/min (31.8 CFM). Max working pressure 12 bar (170 PSI). Made of zinc-plated steel/brass. ISO 6150 B standard, A-A 59439 standard (former U.S Standard MIL C 4109 1/4"). Complies with safety standards ISO 4414 and EN 983.