Obviosly it camo's the mask.
I'm surpised no one has mentioned how well it protects you. Balls just bounce right off. Very nice.
The hang off around the edges also acts to distort the shape of your mask, making some eyes slip right over it.
It is kinda hard to get on, but it's easy once you get the hang of it. I'd say the biggest problem is JT's fault, trying to get the goggle strap out of the goggle.
If you play recBall, buy it. You don't need to be a sniper or anything. It helps everywhere.