Smartwool PhD Cycle Socks. When longer rides require a bit more cushioning, the Cycle Light Elite Mini comes to the rescue. We added light cushioning in the heel and toe without adding in-shoe bulk. Mesh zones on the top of the foot add breathability while the 4 Degree® elite fit system helps the sock stay in place. It’s all designed to keep you comfortable as the miles roll by. Now featuring Indestructawool™ technology for ultimate durability.