Features:Optical axis is suitable for all kinds of electronic equipment / guide rods, drive shafts, pillars.Screw rods are widely used in machine tools, such as 3D printing.The bearing housing has a certain bearing capacity and can be mounted on an ordinary precision rack with strong adaptability.The kit includes optical axis and lead screw, housing bearing, linear guide support, CNC stepper coupler and ball bearing.Flexible shaft coupling.Specification:Optical Axis:Size: Approx. 20.2 cm/ 7.9 inMaterial: SteelFlexible Shaft Coupling:Size: Approx. 2 * 2.5 cm/ 0.8 * 1.0 inMaterial: Aluminum AlloyGuide Shaft Support:Size: Approx. 4 * 3.3 * 1.4 cm/ 1.6 * 1.3 * 0.6 inMaterial: AluminumSliding Block:Size: Approx. 3.3 * 3 * 2.1 cm/ 1.3 * 1.2 * 0.8 inMaterial: AluminumScrew Rod:Size: Approx. 20 cm/ 7.9 inMaterial: AluminumPackage list:2 * Optical Axis1 * Screw Rod1 * For T8 Nut4 * Sliding Block2 * Coupling4 * Guide Shaft Support2 * Zinc Alloy Bearing Block Bearing