Set of four 8" Diameter Flat Free Tires - 4.10/3.50-4" with spacers for Universal fits Commonly used as caster wheels on utility carts, hand trucks, dollies and other utility equipment. Comes pre-mounted on a steel white wheel for quick and easy installation. Comes with a 2.25" offset hub and bearings for a 5/8" axle pre-installed. Includes an adapter kit to fit additional hub lengths. Adapter kit features: (2) 1" spacers, (2) 1/2" spacers. They are suitable for rolling over rough or uneven terrain in areas that may contain sharp debris such as nails, metal shavings, or rocks. The tire has an inner tube that is filled with a solid foam instead of air. Thus, it cannot go flat. Our Flat Free Tires have the bounce and cushion of an air-filled tire with the benefit of no flats because foam filled tires retain approximately 65% of the shock absorption of a pneumatic tire -- softer than solid tires. WEIGHT CAPACITY IS 250 POUNDS