Mens Heat Holders Extra Warm Ultimate Thermal Ski Socks (2.3 Tog) Acrylic, Nylon, Polyester Premium quality extra warm ultimate thermal socks. Fiber: 91% Acrylic, 5% Nylon, 3% Polyester and 1% Elastane. Tog rating 2.3. Extra heavy bulk yarn with excellent thermal qualities. Long pile cushioning adding comfort and support and increases the tog rating.