I looked at Giro's sizing and ordered an M. I'm a 7 1/4 - 7 3/8. I thought I'd have more adjustment, but I'm at end and it seems to be okay. I haven't skied in it yet, but It's very light, the color is cool and the shape seems right on my head.
This review was written in the old system and had content requirements that are different than reviews written today.