... mesh: aluminum net or stainless steel net 3.Function: air filter 4.EN779 class:G2, G3,G4 2012 New Design ... with carboard- Pre filter Application: Filter dust , pre-filter through air filter programType: synthetic fiber foldaway filterFrame: aluminum, paper or galvanizedMedia ... stainless steel netEN779 class:G2, G3,G4,F5Average arrestance:84%-90%(ASHRAE52.1-1992)EUROVENT4/5 class: EU3,EU4,EU5DIN53438 ...