This a replacement standard Dust Cap measure 2.441 for standard 6 Lug Trailer hubs. Dust Caps and Grease Caps are intended for specific greasing purposes. The simple function of the standard dust cap is to keep grease in, and dirt and water out. You would use this version if you either hand-pack you bearings and water a cover, or you use the accu-lube system with a grease fitting on your spindle, and desire a plain cover rather than the accu-lube dust cap. To ensure proper fit you can measure the inner diameter of the outer face of your trailer hub at the location where it would instal. We additionally offer a 2.441 Trailer Dust Cap installation Tool for 2.441 Boat Trailer Dust Caps which makes the process of installation and removal of your trailers dust caps simple and hassle fre