1material:non-woven 2efficiency:G4 3advantage:small wind resistance,long using life, low ... solids etc.;2.Its internal purifying materials may adopt non-woven cloth, nylon nets, active carbon fiber, metal nets, purifying sponges etc ... outside framework is made of paper, aluminum materials or galvanized iron framework;4.It offers G1, G2, G3, G4, GN(nylon ...