Protec antimicrobially treated to help inhibit the growth and migration of mold, algae and bacteria on the filter (Based on internal laboratory test report #SM211AF). Optimized Filter Design maximizes moisture output. Filter captures minerals and pollutants from water & helps prevent white dust. Replacement Filter B Protec antimicrobially treated to help inhibit the growth and migration of mold, algae and bacteria on the filter Filter captures minerals and pollutants from water & helps prevent white dust Fits Honeywell model HCM-750 series humidifiers Package contains 2 filters.