First effect filter, which is mainly used to capture the particles of 1-5 m and all kinds of suspended material, is widely used in various air conditioning systems and air conditioning systems, and also used for the primary protection of multi-stage filtration system. This series of products are plate, folding and bag type, frame materials: paper, aluminum alloy, zinc coated steel, filter material: glass fiber filter cotton, activated carbon filter cotton, synthetic fiber filter cotton, non-woven filter cotton.