Welded steel heavy duty swivel caster. Heavy duty wheel with Blickle Extrathane®. polyurethane tread, with cast iron wheel center. Bracket: Sturdy welded steel construction, with double ball bearing in the swivel head, additionally reinforced by the integration of four specially shaped and hardened bearing seats, swivel head seal with labyrinth design, fitted grease nipple, bolted and secured with a welded very strong central kingpin. Bolted wheel axle. Zinc-plated, blue-passivated, Cr6-free.