Polyester Needle Punched Felt used for dust collection filtration,polyester needle felt filter bag has excellent performance Material: Polyester fiberWeight (g): 500 Thickness (mm): 2. 0mm Air Permeability (L/ ... them with singeing, calendering, heat setting, Teflon coating and membrane. polyester needle felt adopt nonwoven workmanship, with the property of stable physical dimension ...