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 3 3/4 in Nominal Width 1/8 in Actual Inside Dia 3.359 in Actual Width 0.139 in Dash Number 237 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 3 5/8 in Actual Outside Dia 3.637 in FDA Approved No Package Quantity 10