One touch of the Manfrotto 181 central pedal locks (or unlocks) all three wheels simultaneously. Lift the pedal and a cam action raises the wheels off the ground and the weight of the tripod and dolly rest on separate feet. Weighs only 9.9 lbs, with a diameter of 50". Accepts tripods with rubber/metal retractable spiked feet such as the 3068 tripod.