General air conditioning systems, textile plants, chemical plants and telephone exchanges and ventilation systems rely on clean air to function efficiently and for health and safety considerations. AUSFIL panel air filters include “Superply”; a rugged metal framed 5 ply construction developed for tough conditions with high efficiency and superior flow capability when used dry. To achieve high efficiencies, “Superply” may be oiled, although this will reduce flow. On the other hand 'Superair' an inexpensive filter using a unique synthetic media with a rigid cardboard frame, exhibiting an efficiency rating of 90% to No.4 Dust, it’s pleated style filters offer 5 times greater flow capability over other commonly used flat media. Unlike the “Superair”, “Superply” units can be cleaned many times and if necessary re-oiled using light spraying oil.