Helps with breathing but one more thing to keep track of
At first I loved it because I could breathe more easily but after a while it didn't feel that comfortable - kind of pressed against my nose, not painfully, but  I was just aware of some pressure.  Also when I took off the mask I had to find a place to put the shield, it  wouldn't stay inside the mask so there were now 2 things to keep track of.  I'm on the fence about this - it does keep the mask cleaner, no lipstick stains, and it does allow you to breathe but I felt I had to keep adjusting it to try and make it pleasanter to wear.  Tried it upside down and right side up but it always seemed to press against my nose .  It fit nicely inside most masks - both homemade and  disposable ones.  I will be so happy when we don't have to wear masks any more.  It's hard for me to hear at the best of times and the mask straps get caught on my hearing aids and sometimes pull them out of my ears .... but I digress.
Rating: 3 stars