These drivable, steerable dollies are designed for maximum versatility and durability. Whether you're moving your sled on grass and dirt, or on a paved surface like concrete or asphalt, Power Wheels Drivable Snowmobile Dollies help you move your sled at speeds up to 5 MPH. The set includes two ski dollies with cotter pin wheel assembly and a track dolly with a caster wheel for non-motorized use. Drive or slide your sled into the shop, up a trailer, or reverse into tight spaces for storage. Improved design incorporates a 31% wider wheel base for increased stability.