Synology Rail Kits are designed for installing your RackStation on the rack. The Synology Rail Kit Sliding comes with sliding rails, making it easy to slide the RackStation in and out for easy maintenance, while the Synology Rail Kit Fixed secures your RackStation on a rack._x000D_ _x000D_ Physical specifications for Synology 1U Rail Kit Sliding _x000D_ **Mount post width must equal or greater than 451mm_x000D_ **Panel width must equal or greater than 480mm_x000D_ **Mounting depth: 660mm~840mm_x000D_