Bamboo-carbon nano technology involves impregnating cotton yarn with nano-sized particles of bamboo charcoal. The bamboo-carbon nano emits far infrared rays onto the skin, giving the socks excellent thermal properties, making them ideal for winter use. Bamboo-carbon nano also promotes blood circulation and metabolism, and because it has anti-bacterial and anti-fungal properties, acts as a deodorant. Bamboo-carbon nano socks have powerful moisture absorption qualities, drawing perspiration away from the skin. Repeated washing will not diminish the efficacy of the socks.