grade ABEC-1, max rpm 34000 with grease. Pre-lubricated with grease, less friction, no maintenance needed Single-row ball bearing for applications support and axial loads Easily removed and reinstalled.perfect for moderate load uses: skateboards, Inline skates, scooters, inline blade electric motors, wheels of bicycle, motorcycle, electric hand tool . in many other rolling applications Repalcing the worned ones on your skatebord scooter inline blade electric motors, wheels of bicycle motorcycle,automobile, electric hand , etc in many other rolling applications. Please do check dimensions/size or the 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 standard. This light duty bearing has an 8 mm bore diameter, a 22 mm outside diameter, and a 7 mm width. 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 greater than 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 coming into contact with each other during , reducing friction, vibration, and noise. Removable single lip contact seals on both sides against contaminants and retain lubrication applied at manufacture. This ball bearing is suitable for 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 the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.