No where new one size fits all
I’ve never had an issue with hat sizing especially on on-size fits all hats. Never even had to use the last option to size up. Even at max stretch, this hat was so undersized and tight that I began to get a headache and see spots within a few miles of my run. In the end, I had to give it to my 13-year-old as they were the only one in the house who it fit. Bummer because I really like the construction, super lightweight, and felt like high quality. Shame as well because it wouldn’t be hard to simply add more elastic on the strap to make it more of a one-size fits all. There is even space to tuck away any extra cord.