Beaver Reg/Valve O-Rings Euro Type - Standard Fits between European type cross flow cylinder valve and A-Clamp regulator 1st stage. Note: These are a harder O ring correct for High Pressure Use. Soft O rings are for lower pressure applications and will extrude, stretch in diameter when under pressure and fall out when regulators are removed. Features: Cylinder Valve O Ring Fits between Regulators and Cylinder Valves Type 111 measuring 11.00 mm by 2.62mm thickness 10 per pack