Description:  250/300/500/550mm Linear Rail Guide Linear Sliding Guide Block CNC Tool.     Specification:  Height (Block): 10mm.  Width (Block): 27mm.  Length(Block): 46mm.  Height (Rail): 8mm.  Width(Rail): 12mm.  Length(Rail): 100mm/200mm//300mm//400mm//500mm.  600mm//700mm//800mm//900mm//1000mm.  Rolling bearing seat material: Bearing steel.  Quantity: 1pcs.     Features:  High precision, smooth, high wear resistance and low noise.  Advanced production technology, precise products, high hardness and durability.  High bearing capacity and low friction.  Widely used in CNC machine tools, machining centers, electronics, automated machinery, textile machinery, automotive woodworking machinery, printing machinery, etc.     Installation Precautions:  When installing, do not remove the plastic rail in the slider in advance, otherwise it will easily cause the steel ball in the slider to fall out during assembly and cannot be installed and used normally.     Installation steps:  1. Align the end of the rail with the slider.  2. Use the guide rail to slowly push out the plastic rail.  3. The plastic rail falls naturally until the slider is completely loaded into the guide rail.     Note:  Please note that the package includes one size set or one single linear block only.     Package Included:  1 x Linear Rail + MGN12H Linear Rail Guide Block or.  1 x Linear Rail Guide Block