... functions ; Super quality and low price . Dust Removing Needle-punched Filter Felt CharacteristicIntroduced non-woven technics and ... include polyester , polypropylene , anti-static , water-proof and oil-proofing , glass fiber , special fiber filter material and ... -treatment techniques such as singeing , calendering , water-proof and oil-proofing , composite , coating , impregnation and filming , ect. ...