SmartWool Women's Phd Cycle Light Mini Socks - Past Season 65% Merino Wool, 33% Nylon, 2% Elastane Light Cushion: Light cushioned sole for added warmth with minimal volume. PhD = Built for Performance in the Highest Degree. 4 Degree Elite Fit System: Uses two elastics for greater stretch and recovery to keep the sock in place. ReliaWool: Patented ReliaWool technology in high impact areas provides superior durability. Strategically placed mesh ventilation zones provide ventilation for temperature and moisture management Virtually seamless toe Sock Height: Mini - 3.75" overall height Style: SW0SW078