This sock is very similar to our J.B. Expedition Thermal Backpacker Sock and was designed for rugged outdoor activities such as backpacking, camping, hunting/fishing, hiking, and trekking. It features a unique blend of Acrylic, Wool & Hollofill and has a thick cushion making it ideal for Fall / Winter and boots. Suitable for weather up to -20 Below. With extensive field testing the results are clear, the J.B. Extreme Power Hiker provides the best in comfort, value, and quality of any sock. We are so confident that you will like our socks all of them come with our No Risk Guarantee, best of all they are made here in Canada!