This model is a housing for a modified computer case fan to make your own air purifier. I use mine as an air purifier next to my A1 Mini.
This model is designed for a 90mm case fan. I pulled one out of my old pc and converted it to be USB powered with an old IPhone charger.
I am using a sheet of Activated carbon as my filter cut to fit the slot in the case.
The author marked this model as their own original creation.