I use the revisions with the built in fan I got from Bob at Bent Barrel Airsoft.
Considering I'm a fat old guy who has always dealt with fogging issues, especially when it is humid/raining out, I have not had a fog over issue with the Revisions since I made the leap and spent the extra $$ to buy them.
Have not had to remove any foam or add any fog tech to date.
Saskatchewan Age Verifier! Contact for more Info.
http://airsoftcanada.com/showthread.php?t=174161 - Honour & Respect your fellow players! #Airsofthonourandrespect