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 5 3/4 in Nominal Width 1/8 in Actual Inside Dia 5.7 in Actual Width 0.139 in Dash Number 256 Color Black Durometer 80 Shore A Nominal Outside Dia 6 in Actual Outside Dia 6.012 in Temp Range -55 to 300 Degrees F FDA Approved No