wow I have used this on my goggles for nearly 3 months and every time out it has kept everything from fogging up. I now have none of the problems since I put this on. It makes noise but not too much(you can hear it but not to where anyone could pinpoint you where you are) just above a whisper.
I have yet to find anything wrong with this product exceeds expectations.
I wear glasses an live in georgia. In order to see I must wear my glasses underneath my goggle setup. the problem that I was that my goggles were fogging up due to the humidity. I have a thermal lens so that wasn't a problem but even after using rainx they were still fogging up to the point that I couldn't see. After putting this on my goggle system I have had no problems even durring the summer when the temp and the humidity are extreme. my glasses now have no problems with fogging. If you wear glasses and have a fogging problem then don't hesitate buying it. worth every bit of the 30 dollars i spent on it