The Washable Brisa Cartridge Filter is designed to ensure the highest air quality in your home. With two electrostatic filters, the Brisa Cartridge Filter first eliminate large airborne particles and then charges the smaller particles such as pollen, mildew spores, dust and other allergens, trapping them in the filter plates. You can breathe easier knowing that Brisa is leaving you with cleaner, fresher air. 1 filter per package