-Height designed to protect the childs back. -Light weight trolley made in Aluminuim. -Break proof flexible plastic (polypropylene copolymer). -Anti-Roll design. -Up to 15 Kg Weight. -Silence flexible silente PVC wheels. -Large platform base for QWbetter backpack protection. --Special hook to attach to the backpack. -The base is designed with different holes to attach the straps of all kinds of backpacks.