ACE Pack of 10 8 mm LM8UU Linear Motion Bush Bushing Ball Bear Bearing LM Series Linear bearing ball cage, hardened coat of both ends ring. Bearing various parts of the size has been standardized, interchangeable, and do not have to worry about replacement of worn. Ball in the cage loop to run a smooth ball guide surface to ensure even if high-speed operation, low noise. Size : 0.8* 2.4 Color : silver