The Electrolux Purea9Air Purifier Includes The Pure Sense System That Continuously Monitors Indoor Air Quality And Automatically Adjusts The Fan Speed To Deliver More Optimal Air. Enjoy Peace Of Mind And Cleaner Air With This Hepa Filter That Captures 99.97% Of Allergens Down To 0.3 Microns In Size. Plus, Manage Your Air Quality From Anywhere With The Electrolux App.