This tool-less snap-in filler panel is an ideal solution to fill open rack units in racks and cabinets where separation of cold air and hot air is required. These panels are designed to be installed without tools and snap-in to 19in EIA/ECA-310-E compliant tapped or 3/8in square hole mounting rails without modification. The patent pending design does not require field modification to fit a tapped hole and the panel can be swapped back and forth between cabinets or racks with tapped or square holes as necessary. The specially designed clips allow the panels to snap into mounting rails as thick as 0.187in (typical EIA rack) or as thin as 0.078in (some server cabinets).These panels are designed to work effectively with equipment and flat, angled or curved patch panels. Ridges along the top and bottom rear edges of the panel make a seal without creating a tolerance build when using multiple filler panels.