[daishi]

The ops gear anti fog doesn't work as good as fogtech Ive found.

Also, a big problem is people WIPE the lenses...which removes the fogtech. Don't touch your lenses at all...if there is some condensation shake your head and let it drip out the bottom...which is where you riped the foam off.

But hey, if you absolutely think you need a fan go for it. And as David said.... the fan will be quiet..as in people wont be able to hear it, but you certainly will hear the damn thing vibrating through your head gear.... just think of constantly having a mosquito buzzing beside your ear.