7"x17" PP/PE needle Felt Filter Bags 1.Material:Needle felt PP,PE 2.Welding or Sewing 3.Plastic Ring or ... Steel Ring 4.Size, 7"x17" PP/PE needle Felt Filter Bags were made by PP,PE,Nylon,Nomex and ... with filter bag vesse together. 7"x17" PP/PE needle Felt Filter Bags1).Nominal micron filter bags (#1,#2,#3, ...