The Auto Dolly is placed under each tire of the vehicle, making the vehicle a rolling cart that will now roll in any direction with ease. The large roller bearing casters make it simple for anyone to move the vehicle in any direction. Like all of our casters for The Auto Dolly, the standard caster contains a mar-resistant polyolefin wheel that also features a crown profile. The crown profile wheel means less rolling resistance in contact with the ground. The wheel profile also helps to pinch small debris out of the path, rather than coming to a screeching halt. The Auto Dolly comes in three sizes: 8 inches, 12 inches, and 16 inches wide. Auto Dolly Attachments are only available for the 12 and 16 inch dollies.