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 5 1/4 in Nominal Width 1/8 in Actual Inside Dia 5.234 in Actual Width 0.139 in Dash Number 252 Color Black Durometer 90 Shore A Meets/Exceeds ASTM D2000 NBR 90 Nominal Outside Dia 5 1/2 in Actual Outside Dia 5.512 in FDA Approved No Package Quantity 5