Medium efficiency filters are mainly used in central air conditioning and central air systems. It can be the primary filter for air conditioning systems in order to protect the system under a filter and the system itself. With its unique patented bag structure to ensure airflow evenly fill the entire bag. Possible and to prevent leakage of overcrowding between bags. (Types) Type: plate, folding, bag, (Materials) Material: cold plate spray, aluminum, galvanized sheet, (Filtration materials) Filter material: non-woven fabrics woven (Filtration effect) filter Efficiency: 60 ~ 60%, 80% ~ 85%), 90% ~ 95% (colorimetry assay) (European standard) F5 (dark yellow), F6 (green), F7 (purple), F8/F9 (Light yellow, white) (Thickness) Frame thickness: 22mm, 25mm (Lengths) bag length Length: 381mm, 450mm, 500mm, 550mm, 600mm