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 Medium Hard Nominal Inside Dia 26 in Nominal Width 1/4 in Actual Inside Dia 25.94 in Actual Width 0.275 in Dash Number 475 Color Black Durometer 70 Shore A Meets/Exceeds ASTM D2000 NBR 70 Nominal Outside Dia 26 1/2 in Actual Outside Dia 26.49 in FDA Approved No