The typical low pressure thermoplastic hose is a 3/8-inch male at the end that screws into the first stage LP port, and at the other end youll find a 9/16-inch female that screws onto the second stage regulator body. All our fittings have the anti frictions system in the zone of be too tight of the regulator. We make diverse lengths of hose to adapt them to the needs of all the divers, so much sports as tech diving. Length is measured from end to end of hose, including the fittings and their threads.