Description Material: Carbon steel is known for its excellent strength and durability, it also is a cost-effective material choice for deep groove ball bearings Double-shielded bearings Offer a physical barrier against larger particles and moderate amounts of dirt or dust, extending the bearing's service life and maintaining optimal performance. Wide Application: Widely used in various small-scale applications, including RC cars, skateboards, inline skates, 3D Printers, and industrial machinery where compact size and smooth operation are required. Selecting Guide Open Type (No Designation Suffix) - Suitable for high-speed and even very high-speed operation. Shielded (Designation Suffix Z/ZZ) - High speed. Protect from dirt and debris. Sealed (Designation Suffix RS/2RS) - Made of sheet steel reinforced nitrile butadiene rubber (oil- and liquid-resistant). Lower limit speed than shield bearings. Specification: Model: 608ZZ Inner Race/Outer Race Material: Carbon Steel Shield Type: Double shield Size: 8x22x7mm/0.31x0.87x0.28inch(Inner Dia.*Outer Dia.*T) Number of Packs: 20pcs x Miniature Deep Groove Ball Bearings