Contains one Pre-filter element with ASHRAE 85% high accumulation media, 55% efficiency at 0.3 microns, and 25 square feet area. High-capacity mini-pleat design with solvent-free separators, patented expanded polystyrene (EPS), CFC-free construction. This IQAir Pre-Filter element is for use with the IQAir HealthPro units. These pre filters have a filter life of 6-18 months.