Coating: None Inside Diameter (in): 20.77 Material Description: NBR is a versatile material with good abrasion and cut resistance. It works well in Air, Engine Oil, Diesel Fuel, Coolant/Urea, Hydraulic Oil and Automatic Transmission Fluid applications. Do not use with Biodiesel. Cross Section Diameter (in): 0.1 Material: NBR - Nitrile Notes: Dimensions and Material Descriptions provided for reference only. Color may differ from image.