Marlin 4 is the perfect gateway to light trail riding. It's ideal for new riders who want a mountain bike with knobby tyres that can double as a rugged local commuter. Mechanical disc brakes, front suspension, 21 speeds and mounts for a rack and mudguards make this versatile, fun ride. General sizing indicator! 13.5" size usually suits 9-10 year old's. 15.5" size usually suits 11-12 year old's. 17.5" size and above for 12 year old's through to adults.