Self-heatingThe self-heating principle of the tourmaline at the bottom, with mild heat, and has a warming effect on the feeling of cold feet. Suitable for Outdoor Activitiesskiing, snowboarding, hiking, , camping hiking, riding motorcycles, etc. If you have any question contract us, we will provide the best solution for you within 24 hours. Comfortable and BreathableIt is made of high-quality polyester cotton, soft and comfortable, and has a long service life. One size fits most men women or teens. Humanized Foot-fitting DesignFits the Curve of the Foot So That the Hot is Close to the Sole Skin. MultifunctionalIt can be used to massage the acupuncture points of the feet, the nervous system, and promote blood circulation.To stimulate acupuncture points. Daily use any time of day. Wash under running warm water without detergents.