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 7/8 in Nominal Width 3/16 in Actual Inside Dia 4.85 in Actual Width 0.21 in Dash Number 352 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 5 1/4 in Actual Outside Dia 5.27 in FDA Approved No Package Quantity 2