Marathon Flat Free tires are solid tires made of lightweight, micro-cellular polyurethane, eliminating downtime caused by flats. The airless tires are non-marking and provide the bounce and feel of air-filled tires. Marathon Industries manufactures flat-free tires for construction, industrial, lawn and garden, roofing, rental, concrete, material handling and other related industries. The tires are mounted on a heavy-duty steel rim with shielded ball bearings, and the polyurethane foam is much stronger than rubber, making it nearly impossible to wear through the surface. The solid tire is dense at the surface and strong throughout, so that even if the outer surface does become worn, the tire will still perform extremely well. The foam is similar to rubber on chemical resistance but is not affected by UV rays or ozone. Marathon Flat Free tires are available in various sizes and configurations.