Cast brown elastic polyurethane in hardness 93°Shore A with a convex tread offer a very low rolling resistance, smooth and noiseless running. The convex tread gives less contact area and reduced swivel resistance, which makes it suitable for manuelly operated trolleys. It is floor protective and non marking. The tread has a high abrasion and cut resistance, and is resistant to oils, fats and a wide range of chemicals. It is elastic and recover to round shape after static load, and has a high resistance against picking up cuttings, gravel etc. The aluminium centre reduces the weight of the wheel, compared to a wheel with cast iron centre.