Speciality: G3/G4 ; Workable many times after dust collecting or cleaning,which is economical; Its used to prefilter or coarse filter in the inlet of general ventilation and air conditioning program;its processed by high performance synthetic fiber of gradual density; It has large dust holding capacity and low resistance;inlet side and outlet side are different. SP-30 bule&white color, bule side is air inlet side and white side is outlet side. Temperature resistance: 100.C-120.C Its widely used in plank filters and porket filters