Aramid fiber filter bag PTFE membrane 500gsm1.8mm heat-resistant and wear-resistant used in dust removal and filtration industry. $15.90 - $18.60 / Piece. 100 Pieces (Min. Order) Customized polyester filter bag 500gsm thickness 1.6mm 130degree surface treatment calendering singeing matching filter bag cage. $9.20 - $13.20 / Piece.