Smartwool Women's Phd Run Light Elite Low Cut Socks 52% Merino Wool, 45% Nylon, 3% Elastane Made in USA Style: SW0SW211 Narrower profile provides perfect women's-specific run fit. 200 needle construction provides highest knit density while maintaining ultra light weight Light Elite Cushioning: Maximum impact protection with targeted cushioning on the ball and heel of the foot. Designed specifically for runners. 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 Virtually seamless toe Sock Height: Low Cut: 2.25" overall height