SCUBA Standard 11/16inch Tank DIN Valve DuPont Viton 112 O-Ring (10 pcs) [Bonus O-Ring Pick] Universal DIN Valve to DIN Regulator O-Ring 100% Viton Type A Material, 90 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