The RED Theory is basically the Hi-Fi with a little semi brim. The brim provides a little bit of protection so snow doesn’t get into the top of your goggles and then allow them to fog up easier. It’s light and not that well ventilated. However it does seem to have some sort of goggle vent similar to what smith helmets make. One new thing is the Theory helmet has an inflatable layer inside to adjust to your head instead of adjustable plastic. As long as you aren’t around sharp objects the Theory will do a good job adjusting to your head size and we’ll see if this is added to other helmets or duplicated by other companies. The theory has a few tiny vents that if you want them closed out you will have to add plugs but there is so little venting you probably won’t need it. RED’s audio system isn’t bad. We liked the old system with the mute button on the ears but these inserts aren’t terrible. All in all the Red Theory helmet isn’t going to be the choice for anyone who need’s a lot of venting but it does a good job adjusting to your head.