AIR FILTER VENTILATION SYSTEM; FRAME TYPE: CARDBOARD OR WOOD; FILTERING ELEMENT: SYNTHETIC FIBER PLEATED; WIDTH: 597 MM; HEIGHT: 597 MM; THICKNESS: 48 MM; MEDIUM EFFICIENCY FILTER, TOTALLY DISPOSABLE; METAL PLEATED BACKING; METAL RIBS; BRAND4: POLIFILTRO S; NP4: POLIPLEAT M4208