Winia Airwasher AWA-909BD Air Humidifier and Purifier All-In-One Removes air dust, allergens and harmful gases in your home The BSS (Bio Silver Stone) filter eliminates 99.99% of germs in the water reservoir Maintains a healthy humidity level of between 40-60% 3 fan speeds, plus an auto mode and sleep mode. Covers up to 600 sq. ft.