Active Crew Sock - Hi Black/OrangeSS21 051 Black Orange against cold weather benefit from BLOODCIRC fiber , Far infrared textiles are made with blends of polymer and nano or micro ceramic powders spun together with synthetic fibers and other fibers into yarns. absorb energy from sunlight (invisible light) or the human body, releasing far infrared ray of 8~12m wavelength back to the human body. supports cardiovascular health. Far infrared light has also been associated with an overall