... .It is used as front filter before high efficiency air filter, to reduce the charge of high efficiency air filter, for air engineering plant under normal ... Grade: G1, G2, G3, G4, F5, F6, F7, F8, F9, H10, H11Filter Efficiency: 85~99.9%Air Quantity: 1500~5400m3/hSizes• Ø 590 ...