Shepherd Hardware 8" pneumatic wheels give mobility to heavy loads on smooth, hard surfaces and concrete floors with obstructions. Recommended for the protection of both loads and floor surface. Caster can also be used for outdoor terrain Wheel absorbs shock and vibration. Caster swivels 360 degrees. Heavy duty bolted steel wheel hub is equipped with ball bearings and a 1/2" axle. Large diameter main load bearing and thrust bearing assures easy manoeuvring under heavy loads. Sawtooth design rubber tire is rated at 50 PSI and is 4 Ply. Lube fittings for swivel and wheel bearings.