Frame material: carton Frame thickness: 22, 45, 95MM, etc. Porosity:2.0um Filter material: polyester synthetic fiber with high dust holding capacity and low resistance Construction:Panel Filter Maximum temperature: 80â?? Maximum humidity: 99% Efficiency: G3/G4/F5 (EN79) ADVANTAGE Disposable carton air filters can be used in side-access or built-in filter boxes without deformation. A flat screen may block its surface and obstruct airflow, unnecessarily burdening the equipment. This series of folding well filters can accumulate larger dust at the bottom of the folding well, and effectively filter other fine dust on both sides. The higher the folding height, the longer the service life. Folding well media provides better efficiency than traditional fixed or flat media Carton Pre Filter is solid structure, stable filtration effect and longer service life ,robust, efficient, and easy to handle ,low initial pressure loss ,filtration efficiency is stable .