These are amazing. No more mask rubbing on lips and lipstick. I can breathe and talk with ease now. Keep in mind that not every mask fits the same but this works inside a mask as long as it doesn't cause gaps at the side, bottom, or top. The structure still functions in keeping the mask from sucking in when I inhale. I'm quite pleased with this.
I wear a normal medical mask over a KN95 mask when taking public transportation. But when you double mask, because of suction the inner mask always sticks to my mouth and face. I just tried it with this one and it works perfectly! This winter will be much worse than in the spring. So mask up, a double mask if you can, and go get flu shots!
Great product, I am very claustrophobic, and wearing a mask is difficult if it touches my mouth. I tried it with my folded mask and flat material mask. Works for both, easily. I love that I can talk now and not sound muffled! The interesting thing is, it didn’t leave any marks on my face! I wore one all day yesterday under my mask.
/
USD 
