I only Use now KN95 mask because compared to N95 of US standard it is too expensive while kn95 is 300% lower in price.
I bought KN95 as I've heard it's a good mask but after receiving the actual mask, I've seen that there's an allowance in the middle of it.
I went back to surgical mask, it's also cheap and I've bought a box I guess around $4 for 50 pcs. I can't remember.
In India N95 masks with respiratory valves are banned because they found that it is not stopping the virus from spread so which harm more people.And as I said surgical masks are not capable of stopping the virus due to its bigger pore size so as a whole using mask is just and useless expense.