When riding a bicycle in rough terrain, a heavy duty set of front-drive shafts will help reduce shock and provide better performance. This set of two front-drive shafts from Integy are designed for a boy's style bicycle. They are blue in color, but they are designed for a universal fit on most trail bicycles. Both of the shafts are fully assembled and convenient to install. They are the Traxxas Slash/Stampede 4x4 model.