Well it makes you face feel cool and nice.My mask is thermal and they have only fogged once and when they did I switched it on.Vrmmmm.In a matter of seconds all the mayjor fog was gone.It took about a minute for my googles to become totally clear again.This thing can also take a hit but not more than one.I dont have a visor so it got hit.Its aslo very cheap 25 bucks.
Weaknesses:
Well I guess the battery kinda hrad to put in but no that hard.
Conclusion:
A great product.I would highly recomond to anyone. Also if you dont have a thermal mask I would get this before I blinked again.(I suppose)Anyway its a great product at a great price.