30 Bearing 608ZZ 8x22x7 Shielded Greased Miniature Ball Bearings Single-row bearing for supporting radial loads Shielded to keep lubricant in and contaminants out Carbon steel for durability and resistance to deformity under heavy loads 34,000 RPM limit with grease lubrication Dimensions suitable for use in such applications as skateboards, inline skates, and scooters