The ECO21 is a 4 in 1 (Air Purifier+ Ionizer Design + UV Disinfection + Humidifier) ECO22 Descriptions: 1- Air Purifier with 7 stages including the H13 HEPA to capture up to 0.02 Microns 2- Efficient customized DC motor from Japan, very quiet and saves energy. 3- Quiet 30dB / 55dB won't bother your sleep 4- PM 2.5 indicator display 5- Filter replacement reminder 6- Child lock  7- Timer 8- Sleep Mode 9- Smart Mode 10- LED Touch Screen 11- Wind Speed & Quality display 12- Humidifier function