Description: 8x400mm Linear Rail Shaft with 2pcs Shaft Supports and 2pcs Linear Bearing Block.    Specification: Optical Axis: Material:Stainless steel;  Color:Silver;  Diameter:8mm;  Total Length:400mm;    Rail Shaft Support: Material:Aluminum;  Color:Silver;  Hole diameter:8mm;  Total length:41mm;  Height:32mm;    Linear Slide Block: Material:Aluminum;  Color:Silver;  Bore diameter:16mm;  Hole diameter: 8mm;  Total length:33mm;  Height:21mm.    Features: Good wear resistance and strength, high accuracy, hard to rust.  Has good performances, low friction coefficients and long usage spans.  Suitable for Industrial automation equipment, stepper motor rails, such as 3D printers, engraving machine, XYZ module, slider, lifts etc.    How to install: 1. Put Linear Slide Block into the Lead rod.  2.Then the Rail Shaft Support separately install at both ends of the Lead screw.  3. According to the size of you need to adjust the distance between the nut and Mounted ball bearing.  4. Put shaft coupling into the Lead screw beside the Mounted ball bearing.    Package Included: 1 X Optical Axis;  2 X Aluminum Rail Shaft Support;  2 X Linear Slide Block