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 12.1 mm Nominal Width 1.6 mm Actual Inside Dia 12.1 mm Actual Width 1.6 mm Color Black Durometer 70 Shore A Meets/Exceeds NBR 70 Nominal Outside Dia 15.3 mm Actual Outside Dia 15.3 mm FDA Approved No Package Quantity 25