... wound string filter cartridge length: 5'',10'',20'',30'',40'' ; 2. PP filter cartridge are structured loose outer layers 1. HL pp wound string filter ... capacity and extremely and chemical compatibility . 2. pp filter cartridge specification:Filter media: PP (polypropylene) , cotton ;Outside diameter: ... 30mm;Length : 5'', 10'', 20'', 30'', 40'' ;Filter fineness: 1u/5u/10u/20u/30u/50um ; Core material: ...