O-Ring Viton AS568 Dash Number 470 Actual Width 0.275 In. Actual Inside Dia 20.955 In. Outside Dia 21.505 In. Cross Section Shape Round Durometer Rating Medium Hard Durometer 75 Shore A Nominal Width 1/4 In. Nominal Inside Dia 21 In. Nominal Outside Dia 21-1/2 In. Color Black Temp Range -15 Degrees to 400 Degrees F Meets/Exceeds SAE J200 ASTM D2000