Thank you very much for viewing! The item may have been opened for inspection! Thank you for your understanding and cooperation! 1. Screw holes allow you to adjust the installation height. 2. Solid ball - smoother, more balanced, and quieter. 3. Slip pad - effectively reduces damage from switch collisions. 4. High-quality materials - durable. 5. Multi-layer plating - the surface polishing plating has good oxidation resistance, is not easy to rust, and is beautiful and practical. Specifications: Material: Cold-rolled steel Optional color: Black Full extension length: 580mm / 22.8in Adjustable length: 70mm / 2.8in Size: Approx. 356 * 32.5mm / 14.0 * 1.3in Package List: 2 * Keyboard rails 1 set of screws Monitor calibration is not the same. The color of the items displayed in the photos may be slightly different from the actual object. Please take the real one as standard. 350 MM Cold-rolled steel rail home interior small keyboard two-section guide