The Glasfloss Z-Pak Series frame shall be a rigid construction of 26 gauge galvanized steel. A heavy gauge, galvanized steel header is optional for the Z-Pak Series. The media shall be a high density synthetic fiber or a microfine glass fiber. The filter media pack shall be constructed by pleating a continuous sheet of media into uniform spaced pleats, which are separated by flame retardant, injection molded plastic media separators. A heavy-duty expanded metal reinforcement shall be laminated to the air exit side of the media by a thermo-setting adhesive to maintain continuity of the radial pleats. The expanded metal shall be galvanized to resist rust and corrosion. Metal vertical brackets shall be utilized to stabilize the media pack and prevent air bypass. The air entry and air exit side shall be fitted with two 26 gauge support struts. The pleated media ends are sealed to the top and bottom of the metal frame to prevent air bypass. Gasket material, 3/4″ in width and 1/4″ in thickness, is optional. Glasfloss Z-Pak series filters shall be rated to withstand temperatures up to 180 degrees Fahrenheit. Glasfloss Z-Pak filters shall be Classified under U.L. std. 900.