O-Ring No Metal Detectable No X-Ray Detectable System of Measurement Inch Cross Section Shape Round O-Ring Material Buna N Durometer (Hardness) Rating Very Hard Nominal Inside Dia 4 1/2 in Nominal Width 3/32 in Actual Inside Dia 4.487 in Actual Width 0.103 in Dash Number 157 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 4 11/16 in Actual Outside Dia 4.693 in FDA Approved No Package Quantity 2