O-Ring No Metal Detectable No X-Ray Detectable System of Measurement Metric Cross Section Shape Round O-Ring Material Buna N Durometer (Hardness) Rating Medium Hard Nominal Inside Dia 18 mm Nominal Width 2.5 mm Actual Inside Dia 18 mm Actual Width 2.5 mm Color Black Durometer 70 Shore A Meets/Exceeds ASTM D2000 SAE J200 Nominal Outside Dia 23 mm Actual Outside Dia 23 mm Temp Range -40 Degrees to 250 Degrees F FDA Approved No Package Quantity 100