These wheels have polyurethane treads that provide more resistance to abrasion and chemicals than rubber treads. They also provide quiet rolling and will not mark floors, making them well suited for use in locations where noise must be minimized and an attractive floor appearance must be maintained. Polyurethane tread standard wheels are available in a range of hardnesses. In general, soft treads offer more cushioning and better floor protection than hard treads, and hard treads provide more weight capacity, better abrasion resistance, and easier rolling than soft treads.