O-Ring No Metal Detectable No X-Ray Detectable System of Measurement Inch Cross Section Shape Round O-Ring Material HNBR Durometer (Hardness) Rating Medium Hard Nominal Inside Dia 3 5/8 in Nominal Width 1/8 in Actual Inside Dia 3.6 in Actual Width 0.139 in Dash Number 239 Color Black Durometer 80 Shore A Nominal Outside Dia 3 7/8 in Actual Outside Dia 3.887 in Temp Range -55 to 300 Degrees F FDA Approved No