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 8 mm Nominal Width 2.4 mm Actual Inside Dia 8 mm Actual Width 2.4 mm Color Black Durometer 70 Shore A Meets/Exceeds NBR 70 Nominal Outside Dia 12.8 mm Actual Outside Dia 12.8 mm FDA Approved No Package Quantity 50