4pcs LM20LUU 20mm Long Type Linear Ball Bearing Bush Bushing 203280mm for DIA. 20mm Linear Shaft Rod DIY CNC Long Type 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 : 20*32*80mm Color : silver