The Aerostar® Series 400 pleated air filter utilizes a state-of-the-art 100% synthetic media to achieve exceptionally high levels of efficiency with the lowest resistance to air flow available. The Series 400 filter is extremely effective in removing many airborne irritants such as pollens, molds, dander, and dust. The low resistance improves air flow and can greatly reduce energy costs. This filter can be a valuable tool in achieving points for USGBC-LEED certification projects. Available in nominal depths of 1″, 2″ and 4″.