... Steel Ring 4.Size, 7"x17" PP/PE needle Felt Filter Bags were made by PP,PE,Nylon,Nomex and Oil Absorbent.And they ... filter bags (#1,#2,#3, 4 ) 2).Absolute micron filter bags.(#1,#2,#3, 4 ) 3).Long time filter bags.(#1,#2,#3, 4 ) 4).High flux filter ... bag.(#1,#2,#3, 4 ) 5).Oil absorbed filter bag.(#1,#2,#3, 4 ) 6).High efficiency filter ...