Castelli socks are iconic in the cycling world. Made in Italy, these socks are a work of art. The quality is 10 out of 10.
I own several pairs of Gregge 15 and Castelli Quindici (15) wool socks. Love them both. The only difference I can tell is that the color schemes are different. Castelli officially rates them both for use in 60° F down to freezing weather (with shoe covers!).
Sizing: The sizing chart at the official Castelli website is correct.
I bought these socks when I was buying several pairs at the begining of the riding season. These are great, a little on the thicker side so I like them on cooler days. Stay up well and super comfortable.