Therm-Ic Powersocks Heat Fusion Uni Heated SockTherm Ic thick, heated socks in merino wool. Reinforced to protect the main ar eas of support in the shoe for op timal comfort. They provide up to 16 hours of heat, depending on the battery chosen. You can also use Bluetooth to easily adjust the level of warmth from your smartphone. Features: 54% Merino Wool, 33% Polyamide, 11% Acrylic, 2% Lycra Reinforced heel and toe Ankle and instep protection Micro aerated foot arch for good moisture management