• Ball bearings made of high-quality carbon steel, resistant and durable • Processed with advanced technology to ensure excellent strength and wear resistance • Do not deform easily under heavy load working conditions, allowing stable operation and prolonging service life • Exact dimensions: inner diameter of 8 mm, outer diameter of 22 mm, and thickness of 7 mm, ensuring compatibility with different equipment • Low friction, high speed, and strong load resistance, support large radial and axial loads • Suitable for skateboards, inline skates, scooters, small watches, hard disk motors, stepper motors, and other fields • Iron cover on both sides that prevents the entry of lubricants and impurities, improving performance and durability