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 1/4 in Nominal Width 1/4 in Actual Inside Dia 5.2 in Actual Width 0.275 in Dash Number 431 Color Black Durometer 80 Shore A Nominal Outside Dia 5 3/4 in Actual Outside Dia 5.775 in Temp Range -55 to 300 Degrees F FDA Approved No