410x350x4, 4.10x3.50-4, 410x350-4 flat free sawtooth tire. Must have a 3pc split rim to use. have Manufactured using revolutionary casting process, the Martin Wheel polyurethane airless tire eliminates the need for maintenance. The unique micro-cellular polyurethane structure eliminates the possibility of ever going flat or losing form. No air, no flats, non-marking, oil resistant, solid tire.