Originally designed for a customer who need to move an over-sized load, the auto dolly is a specially reinforced version of our 16" Dolly that also features SIX high capacity casters. 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 entire line of auto dollies are made of super-strong 3/8" steel not flimsy stamped steel. This set of dollies have a specail built in handle for ease of movement and carrying.