I received this hat a bit before Christmas. Wow. It is light, fits wonderfully, is amazingly warm walking around at -5ËšF, but somehow also breathes well and doesn't overheat trail running at 30ËšF. That's impressive.
Everyone in my family tried it on, from our 3 year old on up and they all want one, and it nearly fits them all. Truly one size does fit most (not our 2 month old, and a bit big on our 3-year old). I usually wear a large size hat.