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 Very Hard Nominal Inside Dia 41 mm Nominal Width 4 mm Actual Inside Dia 41 mm Actual Width 4 mm Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 SAE J200 Nominal Outside Dia 49 mm Actual Outside Dia 49 mm Temp Range -40 Degrees to 250 Degrees F FDA Approved No Package Quantity 25