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 3/16 in Actual Inside Dia 4.475 in Actual Width 0.21 in Dash Number 349 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 4 7/8 in Actual Outside Dia 4.895 in FDA Approved No Package Quantity 2