Credible. Far-infrared socks, also known as negative ion far-infrared socks, are a new type of health socks with far-infrared fibers as the main component and elastic fibers woven. They adopt the structure of polypropylene fiber, the outer layer is pure cotton, the inner layer is health care fiber, and elastic fiber is added, which can give full play to the personal health care function of health care fiber and increase the moisture permeability of socks. The principle is that it has dual functions of negative ion and far infrared, and releases 8- 15um far infrared band. The emissivity of negative ions is above 75%, which can improve the blood circulation of feet and neutralize the acidic substances produced by sweat. It is well-known in the market and has been unanimously recognized by consumers, so far-infrared socks are credible.