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 20 mm Nominal Width 5 mm Actual Inside Dia 20 mm Actual Width 5 mm Color Black Durometer 70 Shore A Meets/Exceeds NBR 70 Nominal Outside Dia 30 mm Actual Outside Dia 30 mm FDA Approved No Package Quantity 10