Handbook volume: AR310587+AR310452+AR310451This product includes :CVD-2PCSScrew Shaft 5x5 -2PCSProduct major function & use:Lead the tires & tires to create smoothly1. Generated by harden metal #45, stronger and great durability to accomplish smooth driving performance.2. Better dogbone with diameter increased from 5mm to 6mm.Same as originalLength of dogbone : 85mm