G1-G4 Primary Air Filter Plate Pre Filter For Pre Filtration Of Air Conditioning System Product Description Structural design: A modular detachable structure is adopted. Usually, an aluminum alloy or galvanized iron frame is used, combined with aluminum alloy angle brackets or plastic connectors for fixation. The frame can be completely disassembled, and the filter material can be extracted separately for cleaning or replacement. Filter material folding process: Fold the flat