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 7/16 in Nominal Width 3/16 in Actual Inside Dia 0.412 in Actual Width 0.21 in Dash Number 309 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 13/16 in Actual Outside Dia 0.832 in FDA Approved No Package Quantity 10