The wurkin stiffs filters are easy to use since they slip into the mask easily and
keeps the mask firm.
I have been very happy with my purchase. The masks are of high quality, very comfortable and the inclusion of a filter is very welcomed. Great purchase, highly recommended
Fits very well and comfortable!
These are great little filters that ship fast right here in the USA
These filters are fantastic, are easy to use with wurkin stiff masks, and they are inexpensive.
As a side note, they ship sooo fast.