Accessories:Hex Adpater-4PCS2x10 Steel Pin-4PCS2x5 Stainless Steel Cap Head Screw-4PCSStainless Steel Washer-4PCSProduct major functions & usage:Connect axle and wheelsMajor advantages of upgrading to this part/product :Made with aluminum durable 6061 T6 material, our special design for the hex to install tightly on the axle.