Oh, I know what you mean. I have a RBK Hockey hat, just the brand, not a team or anything (you can tell it's old due to Reebok hasn't used the RBK moniker since 2008), and it's a one size fits all and one of the most comfortable hats I own. It's the only RBK/Reebok hat I have that is sized that way. Outside of that, you just have to know each brand. For ME, I know that I wear a S/M in Reebok, a M/L in Zephyr Hats, and as far as fitted goes, a 7 1/4 in New Era. I only know these due to owning at least 1 of each.