This is a listing for a Double Lipped Grease Seal for 6 Lug and 8 Lug Trailer Hubs and Brake Drums. This grease seal has an inner diameter of 2.25".The need for this seal is determined by measuring the seal surface on your axles spindle. If you have another grease seal, you are able to measure that one as well. This particular trailer grease seal is used on #42 Trailer Spindles. The Outer Diameter of this seal measures 3.376 inches.