Filters typically last 3 to 4 months of regular, 8 hours per day use but are dependent on what kind of use. Consider a subscription to always maintain a safety stock of filters.
AIR1 filters are only compatible with AIR1 Super Mask.
AIR2 filters are only compatible with AIR2 Super Masks. AIR2 filters have 40% more filtration area for the inlet and 100% more filtration is on the outlet of AIR2 Super Mask than original AIR1 filters.
I purchased this to use any time I’m in public, and it slid around on my head too much for it to be practical. I also had to put my hair in a pony tail or the sliding around caused my hair to cover my face. This made it very cumbersome.