Made of heavy pressed steel, with heavy fork and top plate, very strong bolted and secured central kingpin, double ball bearing in the swivel head, additionally reinforced by the integration of four specially shaped and hardened bearing seats resulting in a very high resistance to shock and impact loads. Bolted wheel axle. Bolted wheel axle. Zinc-plated, blue-passivated, Cr6-free. Made of high-quality, reaction-injected polyurethane-elastomer Blickle Extrathane®, low-noise operation, low rolling resistance, good floor preservation, very high abrasion resistance, high cut and tear propagation resistance, very good chemical connection with the wheel center.