This is a boxed complete Pre Greased Trailer Hub kit for 5,200lb Trailer Axles complete with lug nuts, dust cap, and a cotter key for securing to your trailer axle. 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 6 Lug hub, with a 6 on 5 1/2 standard lug pattern. This hub outfits a 1 1/4 inch x 1 3/4 inch tapered trailer spindle, with a 2 1/4 inch Inner diameter Grease seal surface that is pre-installed as well. This 2 1/4" Measurement would be the diameter of your axles grease seal surface. This hub outfits most standard 5,200lb Capacity Trailer Axles that use Number 42 trailer spindles. The trailer wheel bearings packed within this Hub measure 1 1/4 inch Inner Diameter and 1 3/4 inch, and feature wheel bearing numbers 15123 ( 1 1/4 inch) and 25580 (1 3/4 inch). This hub is prepacked with high-quality, high-temperature wheel bearing grease, and features superior corrosion control and lubrication.