Welded steel heavy duty swivel caster with steel spring. Heavy duty wheel with Blickle Extrathane®. polyurethane tread, with cast iron wheel center. Bracket: Particularly rugged welded steel construction, with axial grooved ball bearing DIN 711 and tapered roller bearing DIN 720 in the swivel head, dust and splash-proof, fitted grease nipple, bolted and secured with a welded very strong central kingpin, rugged fork and hinged plate construction with maintenance-free steel spring mechanism. Bolted wheel axle. Zinc-plated, yellow-passivated, Cr6-free.