Set the groundwork for a strong workout. These socks hug the shape of your foot for a distraction-free fit as you move. Designed for Training. 3D-knit PerformaHeel creates a shaped fit and locked-in feeling. 360 degree arch support. Left and right toe construction for a comfortable fit. Sock back: 95% Nylon, 5% Lycra elastane. Sock middle: 95% Nylon, 5% Lycra elastane. Sock front: 95% Nylon, 5% Lycra elastane.