10pcs 688ZZ Ball Bearing Double Shielded Double Metal Seal Deep Groove Ball Bearings 8x16x5mm Heavy Load 3D Printer Parts. Feature: With strong load capacity, excellent material, widely used, and toughness. Made of carbon steel, with durability and resistance to heavy load deformation, and is shielded to prevent lubricant and impurities from entering. Fine workmanship, high precision and long service life. Satisfaction Guarantee: We strive to provide each customer with the highest standard of customer service to ensure you have a pleasant shopping experience.