The entire sock is constructed of Meryl® Skinlife, which wicks moisture extremely well. It is also bacteriostatic via the addition of silver ions to the yarn, to keep your feet fresh and protected, which is not only desired, but required when you spend several hours a day on the bike, training or racing at the highest level. It is interesting that Castelli didn't opt for the lightest weight or coolest sock construction. Not that the Italia 15 will be out of place during the summer, but perhaps with Worlds in the Fall season, durability, comfort and support were graded slightly more important. The clean aesthetic and sharp color contrasts are ideal for a national team sock, and any fan will love them.