"The CRA20001 is a 19"" 1U blanking panel kit with 10 pieces that can fill up to 10U of rack space. Installing blanking panels in unused rack space improves cooling efficiency inside the enclosure. This optimizes airflow and prevents the recirculation of hot air. Blanking panels can be installed without tools and will fit in any square hole EIA-310 compliant rack enclosure. The CRA20001 is covered by a 5-year limited warranty."