The IST LP Rubber Low Pressure Regulator Hose with Screw-On Valve Fittings is for divers who insist on the rugged durability found only in rubber. These hoses are virtually indestructible and can deliver decades of faultless performance with proper use and maintenance. 3/8 inch (9.525 mm) male fitting screws into a first-stage low-pressure (LP) port. 9/16 inch (14.29 mm) female fitting screws onto the second stage regulator or octopus. 36 inch Low pressure regulator hose, connects the first stage to the regulator Rubber construction for maximum durability Male end screws into a first-stage low-pressure (LP) port Female end screws onto the second stage regulator or octopus