We took the thermal properties of the original blue flame and blended it with the super moisture wicking and evaporative properties of bamboo viscose to keep your feet drier. A dry foot is easier to keep insulated but evne so this sock is constructed with thick loops of cushioning that help trap heat in. This sock rates 4 flames out of 4 for thermal properties.
40% Bamboo Viscose / 40% Acrylic / 15% Polyester / 5% Spandex
EcoSox Bamboo E-Tech Thermal Socks - High Performance Bamboo Viscose