Pamper your feet with nature’s technical fiber: Smartwool's Merino wool. Their PhD Ultra Light socks are extra-thin for an airy, high-performance feel. Wool’s excellent wicking abilities, temperature regulation, anti-odor properties, and softness will make these some of your favorite socks. You’ll also love the supportive feel afforded by the 4-Degree Fit System. And, you can trust these socks to be around for the long run with Smartwool's patented Reliawool Technology.