XUEMEI Foot WarmingThe sole of the socks is designed with tourmaline, which can self-heat to keep your feet warm anytime, anywhere, without electricity, not limited by time and region [Working principle] Foot massage stimulates the acupuncture points of the feet to achieve the massage effect. Wear our tourmaline socks as you walk for a new level of energy and comfort. Promote blood circulationUse high-quality natural hot spots to stimulate foot acupuncture points to achieve massage effect, relieve leg fatigue, regulate blood circulation, and enhance body resistance. Ideal for Outdoor ActivitiesKeep your feet warm in cold weather. Perfect for a variety of outdoor activities, ideal for mountaineering, skiing, winter fishing, jogging, winter hunting, biking, hiking, ice hockey and snow shoveling. ReplaceableThe self-hot spot on the socks should be in contact with the sole of the foot, not the sole. We have prepared two pairs of self-heating socks for you, which are convenient for you to change and clean to keep you warm at all times. ize: all size Color: black+white Packing list: 4pcs