Includes 8 axle washers and 4 bearing spacers from Dimebag Hardware. Speed washers increase speed and promote longer bearing life by reducing friction between the bearing and axle nut and hangar. Having spacers allows you to tighten your nuts down to eliminate and wheel wobble and keep your wheels spinning smoothly and freely. This kit features standard size products and will fit on all skateboard/longboard trucks that have 8mm axles (virtually every truck has the standard 8mm axle size).