This listing is for a Pre-Greased Trailer Hub for 3,500lb Trailer Axles. Not only are the Bearings in this Hub pre packed, but high temperature grease has also been chambered within these hubs, for a truly "ready to go" trailer hub assembly. This particular hub is a Hot Dipped Galvanized 5 Lug hub, with a 5 on 4 1/2 standard lug pattern. This hub outfits a 1 3/8" x 1 1/16" tapered trailer spindle, with a 1.72" Inner diameter Grease seal surface that is pre-installed as well. This 1.72" Measurement would be the diameter of your axles grease seal surface. This hub outfits all standard 3500lb Capacity Trailer Axles that use #84 trailer spindles. If you are needing a Tang Washer or Cotter Pin for securing your pre-packed hub, simply select the Add On Box under the listing title. The trailer wheel bearings packed within this Hub measure 1 3/8" Inner Diameter and 1 1/16", and feature wheel bearing numbers 68149 ( 1 3/8") and 44649 (1 1/16"). The Grease that is packed within this Hub is Lubrimatic Marine and Trailer Wheel Bearing Grease, which has a Calcium Sulfonate base, and features superior corrosion control and lubrication. This makes this Pre Packed hub ideal for all environments.