Glasfloss MR-11 air filters shall be of the extended-surface pleated-media type. The media utilized shall be made of 100% synthetic fibers. The media shall be pleated in a tapered radial configuration. A heavy duty, recycled 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. The pleated cartridge shall be bonded to the peripheral interior of the outer frame. A heavy-duty moisture-resistant beverage board incorporating post-consumer material shall be utilized for an encasing frame. The frame face shall be internally laminated to the pleated cartridge apexes. Glasfloss Z-Line Series SB, ZL, HV and MR-11 filters shall be classified under U.L. std. 900 and shall be rated to withstand temperatures up to 180 degrees Fahrenheit.