a split lens. So this is the split lens style, where the two lenses are actually separated.

There's some that have a split lens with side window. This is the full face with the side

window. On the mask. And then there's also another mask called the frame less mask, which

really, there is no frame to this, there's no hard plastic frame like the one right below.

And this mask is called the frame less mask, there's one solid piece of glass and then

there is no frame on this. It's actually just silicone. Now the way to check to see whether a mask

seals on your face, is to actually put it up to your face, take your glasses off, and.

You want to breathe in slightly through your nose, and that mask should stay on your face

when you do that.