The Belkin RK5030 blanking panel set comes with 6 panels to fill unused space in your enclosure. This set includes 2 filler panels in each of the following sizes: 1U, 2U and 3U. These units mount horizontally within an EIA 19" server rack. Blanking panels block hot air from flowing to the front of your server rack enclosure, keeping your data center equipment clean, organized, and prevents overheating. This unit comes with a standard lifetime warranty.