What are filler panels or blanking panels?

A filler or blanking panel is a flat piece of metal or plastic that matches the height of one or more rack units (1U is equivalent to 1.75″). Typical sizes range from 1-8 rack units.

Filler or blanking panels are used to close openings that are not being used in a rack enclosure. This helps to prevent hot air from mixing with the cooler intake air. The result is more efficient equipment cooling. Nearly all rack manufacturers make filler panels and all 19″ filler panels will be compatible with standard 19″ racks.