NIB SNOW DEER Size M heated socks men or women. Electric battery foot warmer. Material is upgraded to use a specially engineered type of polyester CoolMax . This fabric dries 5 times faster than cotton. Heating Elements Covers Whole Toes,Top&Bottom of Foot】:these battery socks upgraded heating elements covers whole toes, top and bottom of foot.In severe cold winter,select SNOW DEER electric heated socks is very important for people to prevent frostbite.SNOW DEER battery heated socks used 7.4V 2200mAh lithium polymer rechargeable battery .the heating time will longer than 3.7V&5V heated socks and the temperature will be more stable. Also it is with 3 heat setting smart controller for you adjust the temperature easily. Size 6-8.5