Precision grade ABEC-1, max rpm 34000 with grease. Pre-lubricated with grease, less friction, no maintenance needed Single- ball bearing for applications that support and axial loads removed and reinstalled.perfect for moderate load uses: skateboards, Inline skates, , inline blade electric motors, wheels of bicycle, motorcycle, electric hand . in many other rolling applications Repalcing the worned ones on your skatebord scooter inline blade electric motors, wheels of bicycle motorcycle,automobile, electric hand power tools, etc in many other rolling applications. do check dimensions/size or the precision grade if it fits in on your device. This 608- miniature ball bearing has red double seals and a steel cage, and conforms to the ABEC 1 precision standard. This light duty bearing has an 8 mm bore diameter, a 22 mm outside diameter, and a 7 mm width. precision is rated at ABEC 1 by the Annular Bearings Engineers Committee (ABEC), allowing higher speeds and creating lower friction than less-precise , and internal clearance is C3 for slack between the inner and outer rings is CN (normal) to compensate for thermal expansion.heat treated to increase hardness for wear resistance. deep ball grooves in both races support high and axial loads, straight bore fits conventional cylindrical shafts, and nylon cage prevents the balls from into contact with each other during use, reducing friction, vibration, and noise. Removable single lip contact seals on both sides protect against contaminants and retain lubrication applied at manufacture. This ball bearing is suitable for use in skate boarding, inline skating, and other skating applications. colour:Silver + black Material:Carbon steel size:Product size: 8x22x7mm Package Contents: 50* 608- C3 bearings Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.