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. STURDY FRAME - This all-terrain mountain bike uses a high-carbon steel frame that combines quality and performance to resist deformation and stretching. The ergonomic design greatly improves the comfort during riding. 4 INCH FAT TIRE - Width up to 4 inches, 5 times more wear resistance than ordinary bicycle tires. Strong grip and anti-skid, fully able to challenge any terrain, and conquer any off-road trails and urban roads. INSTALLATION VIDEO - The installation package includes all the tools you need to build and maintain your own bicycle. You can inst