Castelli Rosso Corsa 9 Cycling Sock
This sock is great if you like an ultra thin sock that holds up very well. Compared to a Defeet sock, I'd say this one is definately thinner but is holding up just as well. I worn my one pair of these for a few rides and I'm close to saying they are my favorite pair of summer socks. Definitely worth the extra bucks (as is pretty much everything made by Castelli).