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 26 mm Nominal Width 2.5 mm Actual Inside Dia 26 mm Actual Width 2.5 mm Color Black Durometer 70 Shore A Meets/Exceeds NBR 70 Nominal Outside Dia 31 mm Actual Outside Dia 31 mm FDA Approved No Package Quantity 10