Eliminate Downtime! Marathon flat free 4.10/3.50-4 inch tire is the most common size tire for hand trucks and other small equipment such as generators and power washers. Also works great in both rigid and swivel casters. Airless tires have the same bounce, feel, cushioning, and performance as a regular air-filled or pneumatic tire. They are also non-marking and will not be affected by ozone or UV rays, plus they're made of lightweight, solid polyurethane foam and are guaranteed to never go flat. Mounted on a 4-Inch diameter steel rim with a 2.25" off-centered hub and 5/8" ball bearings. The tire is 3.3-inch width with an overall diameter of 10.5-inch. Includes grease zerk.