21-SPEED - Compared with 7-Speed, 21-Speed can improve speed better. Outroad mountain bikes can improve the Speed faster, change the Speed accurately, and save more effort for uphill riding. SHOCK ABSORPTION DESIGN - OUTROAD all-terrain MTB uses shock-absorbing front fork, and the thickened outer wall is more shock-resistant. Thickened shock absorber helps to absorb shocks, which can greatly improve ride comfort.