SIGMA-BETA series AH - AS high efficiency and semi-absolute filters are manufactured with the mini pleat technology, have a very small depth and can be installed in exhaust grilles. AH - AS filters are produced in various sizes with air flow ranging from 66 to 2700 m3/h. All the filters have 69 mm-deep anodized extruded aluminum frame, with steel white epoxy painted protective grids on both upstream and downstream sides. The fi ltering medium is made of micro-fiber glass, water-proof and fire resistant; the mini pleats have continuous thermoplastic spacers, and polyurethane sealant. It is provided with a one-piece continuous half-round gasket. Thanks to the low pressure drop of the filters, the energy consumption level of the fan is very low. All filters are supplied with a label indicating the relevant performance.