This strap attaches to the lower side straps of a full face mask to stabilize the mask and prevent it from riding up on your face.
This prevents the lower part of the mask that is suppose to be under your lips from going into your mouth.
It works on most full face masks, but it may put more pressure on the bridge of your nose, so use with care. The installation instructions are included in the package.
The Mask Stabilizer fits the following masks and may work on others: