​Feature:【Rechargeable 】Powered by 2 pcs 3.7V 2200mAh rechargeable lithium batteries, the winter heated socks can last for up to 7.5H, so you don’t have to worry about the power running out too soon. 【Considee Design】The manufacturing technique of these heated socks are designed according to the structure of the human leg, especially the fits the leg without a sense of pressure, universal for men and women.【Comfortable Tempeure】The heat socks is designed with 3 tempeure levels: high (about 50℃); middle (about 45℃); low (about 40℃). This helps in providing comfort to chronically cold feet due to arthritis, poor circulation and other problems.【Application】The winter heated socks perfect for for all kinds of indoor/outdoor activities in winter, such as skiing, hiking, hunting, fishing, camping, snowboarding, etc.【Perfect Gift】The carbon fibre heating element in electric socks focuses soothing heat on the sole of the foot and the toes, improving blood flow to your extremities, and helping to your feet from the cold, great gift choice for Christmas, Halloween,Thanksgiving, Birthday and other festivals etc.Specification:Material: cotton ect.Color: blackSock height: about 24-37cm / 9.45" - 14.57"Sock circumference: about 14-30cm / 5.51" - 11.81"Foot length: about 21-30cm / 8.27"-11.81"Power source: 3.7V 2200mAh lithium batteries (2 pcs)Charging port: USB/DCTempeure levels: high (about 50℃); middle (about 45℃); low (about 40℃)Package included:1 pair* heated socks1 pair* lithium batteries1 pcs* one for two MICRO charging cable