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 1/8 in Nominal Width 1/8 in Actual Inside Dia 4.109 in Actual Width 0.139 in Dash Number 243 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 4 3/8 in Actual Outside Dia 4.387 in FDA Approved No Package Quantity 5