The Huffy Boys' Extent 24 in 18-Speed Mountain Bike is ready to tackle off-road riding. This mountain bike has 24 inch wheels with wide, knobby tires that help you keep your grip over dirt, grass and mud. A front suspension fork absorbs bumps and gives a smooth ride, while disc brakes and a Shimano rear derailleur ensure that shifting and stopping are just as easy as the ride. The adjustable seat makes it easy to accommodate riders of different heights.