"Solid rubber caster never goes flat. Flat-free casters keep your equipment rolling over the toughest conditions, eliminating costly and inconvenient flat tires. Load handling characteristics are similar to air-filled tires, except now troublesome flat tires are a thing of the past. Great for wheelbarrows and hand trucks. Casters qty. 1 Wheel only, Wheel Diameter in. 12, Material Type Steel, Finish Type Zinc plated, Wheel Type Flat free rubber, Overall Height in. 12, Mount Height in. 6 1/8, Bearing Type Ball bearing, Capacity lbs. 330. 12 x 4.10/3.50-6 5/8in. ball bearing bore Zinc-plated steel wheel and brackets Sold individually"