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 4 in Nominal Width 3/16 in Actual Inside Dia 3.9 in Actual Width 0.21 in Dash Number 345 Color Black Durometer 80 Shore A Nominal Outside Dia 4 3/8 in Actual Outside Dia 4.395 in Temp Range -55 to 300 Degrees F FDA Approved No