Designed specifically for space-constrained, large-shaft assemblies requiring high radial rigidity and minimized weight, the 6921-ZZ is a premium thin-section deep groove ball bearing. Outfitted with dual non-contact metallic shields (ZZ), it delivers exceptional defense against coarse dust and factory debris while ensuring reliable containment of the factory-applied lubrication. Because the metal shields avoid contact friction with the inner ring, the 6921-ZZ maintains minimal running torque and ultra-smooth rotation. This makes it an essential mechanical component for large-bore, weight-sensitive 105mm applications, including industrial robotic joints, heavy-duty rotary tables, and complex automated equipment.