Scuba Standard 11/16inch Tank DIN Valve/Regulator Polyurethane 112 O-Ring (10 pcs) [Bonus O-Ring Pick] Universal DIN Valve to DIN Regulator O-Ring (Size 112) 100% Polyurethane Material O-Rings, 90A Durometer (Hardness) Includes a plastic o-ring pick to easily replace your o-rings Preferred Material For Oxygen and Nitrox Compatibility Manufactured and Warrantied by Captain O-Ring LLC