This is the air purifier i have. It just sits in my room running on low all the time. Recently i had a bad virus, not knowingly, i had the ionizer on… Not a smart move, which made my throat parched, like i would wake up in the middle of the night and have bad episodes of coughing. Regardless, its a great product, very effective and the outer most layer can be washed (i believe it’s suppose to be washed every month, but i washed it my first time 2 weeks ago.. After 1 year of usage). Filters are about 150 RMB and needs to be replaced 6 months i believe. Cheap and effective.