Designed for light and medium weight tripods. The 76mm wheels have a sure-lock feature that raises the wheels free of the ground so that the dolly rests on separate feet. It features a 22 lb load capacity and supports all tripods with a 20" radius (as long as the overall weight of the tripod, camera, and accessories doesn't exceed 22 lb). It features 3" wheels with a sure-lock feature that raises casters free off the ground and lets the dolly rest on separate feet.