O-Ring, No Metal Detectable, No X-Ray Detectable, System of Measurement Inch, Cross Section Shape Round, O-Ring Material Buna N, Durometer (Hardness) Rating Very Hard, Nominal Inside Dia. 22 in, Nominal Width 1/4 in, Actual Inside Dia. 21.955 in, Actual Width 0.275 in, Dash Number 471, Color Black, Durometer 90 Shore A, Meets/Exceeds ASTM D2000, NBR 90, Nominal Outside Dia. 22 1/2 in, Actual Outside Dia. 22.505 in, FDA Approved No