we use polytetrafluoroethylene (PTFE) for membrane. Its surface is smooth with high air permeability, and it is waterproof. It can nearly retain all the particles in the dust gas, furthermore, it can guarantee the largest air flow rate but not increase the running resistance. It is the ideal filter material for dedusting. We largely produce high quality polyester, polypropylene membrane needle punched felt, and special material of membrane felt, such as Aramid, PPS,etc.