"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. Wheel Diameter in. 12, Top Plate Dimensions L x W in. 4 1/2 x 4, Casters qty. 1, Capacity lbs. 330, Mount Height in. 15 1/4, Caster Type Rigid, Bolt Hole Spacing 3 5/16 x 2 13/16, Material Type Solid rubber, Wheel Type Flat free rubber, Finish Type Zinc plated, Foot Brake No, Overall Height in. 15 1/4, Bearing Type Ball bearing. 12 x 4.10/3.50-6 5/8in. ball bearing bore Zinc-plated steel wheel and brackets Solid rubber Sold individually"