Goggle fans are designed to sense humidity and kick in a fan to either circulate air or draw out moisture.
Do they work for Paintball Masks and Paintball Goggles?
Yes they do, they're very effective, we'd recommend the Habervisions which detect moisture and draw it out. Its worth pointing out that a goggle fan can only do so much, if you're right sweaty it wont stop you sweating, it can only do so much, a goggle fan will only compensate so far for a badly designed mask, cheap masks will fog and goggle fans will help, but they're not going turn a pumpkin into a palace, neither can they keep you fog free if your lens is damaged. Before investing in a goggle fan 1. check that your doing everything you can to keep sweat out. 2. Make sure you've invested in a decent goggle system 3. Make sure your lens is free from cracks and blemishes.