i've had the f4, and even with the windstopper it is a very cold helmet, again unless your going 15 MPH through the woods. At any trail speed you will feel the wind, I don't care that it's called windstopper, it doesn't work that well. I've now got a 509 with 509 sinister goggles. Hands down the best setup I've had. I've probably used 5 different motox style helmets over the years and the 509 is the only one I've used that doesn't give me that cold spot on the forehead where the corner of the goggle meets the helmet. 509 helmet is also under 200 (more for the goggles) but it is a great set up, thats all I can say. Coldest riding day with 509 helmet was -15 and it was fine, got a little cold on the lake runs but just ducked behind my 3" windshield.