We have bought these filters since years now and highly recommend them. These filters don’t have glass fibers in them and are highly rated, we use MERV 13. Pleated Air Filters.
These filters are great and pick up quite a bit of dust, dander from my parrots and the air smells fresher when I put the new filters in. I use Merv 13 filters because they are the best filters for my home. I use the 20x20x1 size filter. These filters are a little more expensive, but it's worth it.
I didn’t realize that was per filter. I don’t remember sand that was anywhere in the air, but I haven’t used them yet so I’ll have to wait to see how it goes.