Polyester Cartridge Filter Media Description Johns Manville thermo-bonded polyester spunbond media is a blend of coarse filaments larger than 4 dtex and fine filaments smaller than 1.5 dtex. The filaments of different diameters are laid onto the web in different layers, starting with fine at the filter surface to coarse at the exhaust side.. The fine filaments will significantly increase particle retention and at the same time the coarse filaments will minimize the loss of pressure for low energy usage costs. This innovation technology makes JM cartridge filter media possess both high filtration efficiency and low pressure drop. JM offer 3 weights to the market 170 gsm, 235 gsm and 260gsm. Media with special treatments such as Aluminized (anti-static) and oleo-hydrophobic are available at requests.