The Ravelli ATD Tripod Dolly is an excellent dolly for use with your professional camera and video tripods, light stands, and background stands. The most important feature of a good dolly is good wheels. After all, the point of a dolly is to be able to smoothly move your tripod from one place to another. Unlike less expensive models with smaller plastic wheels, our dolly uses large 3" diameter wheels with all metal ball bearings and a rubber outer surface for an ultra smooth roll. The ATD also features one step easy locking wheels. Once you get the dolly where you want it, all you have to do is "step" on the locks for one or more of the wheels. Some competing models including the best names such as Bogen, Manfrotto, Quickset, and Linhof require that you get down on your knees to "screw" a separate rubber stopper down to the floor to hold the dolly in position. The universal leg locks used will fit nearly any tripod. Many of the tripod dollies offered by the competition including the best names such as Bogen, Manfrotto, Quickset, and Linhof have a fixed attachment point at the end of the dolly legs. Ours has a leg grip which slides along the dolly leg going either closer to the center or out to the end. This allows you to adjust the desired level of "spread" for the tripod you are using. This item also includes a free mini tripod that extends from 4.5" up to 9". It features a mini ball head, extendable legs and is compact enough to travel anywhere.