Made of heavy pressed steel, with double ball bearing in the swivel head, swivel head ball cage sealing, additionally reinforced by the integration of a specially shaped and hardened bearing seat resulting in high restistance to shock and impact loads. The special Blickle dynamic riveting process of the swivel head results in minimal swivel head play and smooth rolling characteristics with an increased service life achieved by the work hardening of the ball race grooves. 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.