Heavy-duty high density polyethylene (HDPE) construction fastened to 0.100" (2.5mm) thick aluminum caster channels with rugged 5/16" (8mm) stainless steel tie down anchors. Plate mounted casters, 2 swivel and 2 swivel with brakes. 5" (127mm) diameter donut neoprene wheels. Load capacity 350 lbs. (158kg) per dolly. Includes 1" (25mm) x 15' (457 cm) long cam buckle strap with hooks. Dolly is designed to transport carriers or milk crates. Stores on top of carrier to save space.