The mask lens has a special anti fogging coating.
Fogging machine A machine which is able to be operated remotely to place detonators on a rail.
It is also important that you purchase a pair of wrap arounds that have "air holes" to prevent any fogging or moisture buildup.
They wrap the eye area most effectively and offer some of the best protection of any style as long as precautions are taken to avoid the fogging up of the lenses.
Another perk of polycarbonate lenses is the built-in 100 percent UV protection, and they also are treated to resist fogging while repelling moisture and dirt.