These heavy-duty wheels are 24" in diameter, 8" wide with a 1200 lbs. capacity each. They are made from polyethylene and are U.V. stabilized. The wheel kit replaces the base plate by inserting into the bottom of the 2" round leg post. The wheels are hollow and fill with water when rolled in, the water releases as rolled out. The kit includes two wheels, two axles and all hardware required. Compatible with Truss dock and Frame Dock.