Because of the history behind the Cyklon model second stage, there is a compatibility issue with modern standard hose fittings and to address this issue Poseidon offers Cyklon specific OEM heavy rubber hoses. These low pressure regulator hoses have a standard 3/8-inch male at the end that screws into the first stage LP port, and at the other end you'll find a fitting compatible with the Poseidon Cyklon second stage regulator body. The hoses have a pressure rating of {500 psi | 35 bar} and are Nitrox Ready.