O-Ring No Metal Detectable No X-Ray Detectable System of Measurement Inch Cross Section Shape Round O-Ring Material HNBR Durometer (Hardness) Rating Hard Nominal Inside Dia 3 1/8 in Nominal Width 1/8 in Actual Inside Dia 3.1 in Actual Width 0.139 in Dash Number 235 Color Black Durometer 90 Shore A Nominal Outside Dia 3 3/8 in Actual Outside Dia 3.387 in Temp Range -55 to 300 Degrees F FDA Approved No Properties Resistant to Chemicals Resistant to Oils Resistant to Water