SCAFFOLDING CASTER WHEEL WITH BRAKE wrapped by polyurethane make lower noise than any other conventional material. Iron-made hub not only makes it can load more weight but also makes the bearing bore has better wear-resistance. As heavy-duty casters, load capacity of up to 800 LBS per wheel, the frame and axle are made of steel, about 5 mm thick. it comes in a size 6″ and 8″.