BALANCED DIAPHRAGM Balanced diaphragm design delivers superior breathing performance even at increased depths. Made with corrosion-resistant marine brass, chrome plated finish. Superior and reliable performance to meet with technical diver requirements as well as the demanding needs of the Cold Water diver. Ventilation rate ( air supply / 3000 psi ): 135 SCFM. Intermediate pressure: 135-145 psi. ( 9.5-10.2 bar High pressure port: ( 7/16"-20 UNF ) x 2 Low-pressure port: ( 3/8"-24 UNF ) x 4 plus swiveling turret DIN.