All Ice Qube Air Conditioners and fan systems use PermaCool™ electrostatic filter media to keep dust and other industrial residues from clogging the condenser cooling air passages. The filter material is a rigid/durable 1/4" corrugated polypropylene media with 10 micron filtration which retains a low resistance to airflow. The filter will withstand harsh factory environments and will not degrade over time. Simple washing or vacuuming is all that is necessary to maintain the filter media over an indefinite period of time. PermaCool's dense 3 layer, 1/4" waffle weave configuration enhances its filtration abilities and creates a rigid electrostatic air filter. Unlike other media which may compress and restrict air flow, PermaCool retains its low resistance design.