4pcs LM8SUU 8mm Linear Ball Bearing Bush Bushing 8*15*17mm for DIA. 8mm linear shaft rod DIY CNC Linear bearing ball cage, hardened coat of both ends ring. Bearing various parts of the size is standardized, interchangeable, no worry if replacement of worn Ball in the cage loop to run a smooth ball guide surface to ensure. Size : 8*15*17mm Color : silver