This is one of the best fitting helmets. I have tried so many, even children's, because I have a small head. This is the only one that fits me properly. There is an adjustable strap in the back of the helmet that rests at the bottom of your head. It lets you tighten or loosen the head space in the hemet, for the perfect head hugging fit. It's light and comfortable as well. Love the vent system, makes it weather versatile. The only downside is that everyone and their mother seems to have it. Seriously, I have seen a lot of parents in this helmet, not to mention my own. Its popularity is only based on the fact that it's such a reliable helmet though. I can't knock it since I feel that it is one of the best helmets out there right now. They just need to release more color combos. So rock it like no one else, and you're golden!