The Alen BreatheSmart 75i is our most powerful air purifier and is highly recommended by Consumer Reports. The 75i includes laser sensor technology to auto-adjust fan speed and color-coded air quality rings show you how Alen is working to remove harmful particles as soon as they re stirred up. Connect the 75i to the Alen app to see air quality metrics 24/7 and control your unit remotely. Cleans up to 1,300 sq. ft. every 30 minutes.• Wi-Fi enabled to monitor air quality and control from your smartphone. Auto-adjusts fan speeds based on air quality conditions. H13 Hepa filter removes 99.9% of dust, allergens, and harmful pollutants down to 0.1 micron. 5 color-coded rings, so you can see what Alen is doing.. Whisper quiet, even on the highest setting. Guaranteed forever with unit registration and filter subscription.