The Glasfloss PTA disposable panel filter uses PolyStrand media to maximize its dust holding capacity. The media is encapsulated between two metal grids to maintain integrity under adverse operating conditions. The metal grids are thermally bonded to the internal sides of a heavy-duty, one piece craftboard frame. The closed corner construction prevents dust laden air from bypassing the media through open corners. The filter frame is clearly marked with size, U.L. classification and air flow direction.