Blanking panels (also known as filler panels or rack spacer blanks) are installed in server racks to maintain proper airflow. Using a rack without blanking panels results in improper cooling which can lead to thermal damage. If any of the vertical space in a server cabinet remains open, the gaps between rack mount equipment causes a change in airflow through the rack and across the components. Blanking panels are available in many sizes from 1U to 6U.