Battery Voltage:2*3. 7V 2200mAh Li- ion Battery. Heating Time: 4- 8 hours ( depending on the outside environment). Heating Temperature: 45- 55 Celsius Degree. Heating Area: Front instep. Suitable Occasions: Rechargeable heating socks are suitable for cold weather projects or winter outdoor sports, winter skiing, camping, riding, motorcycles.Specifications: Battery Voltage:2*3. 7V 2200mAh Li- ion Battery. Heating Time: 4- 8 hours ( depending on the outside environment). Heating Temperature: 45- 55 Celsius Degree. Heating Area: Front instep.Color: Gray Black Package Included:* 1 x Electric Heating Socks( 1 Pair)* 2 x 2200MAh Li- ion Battery* 1 x Charger line* 1 x boxNotes: 1. Only sell main products, not other products.2. Since manual measurement is required, please leave a space of 1- 3 cm.3. Due to screen differences, the color may be slightly different from your expected color, please allow.Remind: After receiving the packaging, please check the packaging and the product carefully. If the received item is defective or has any questions, please contact us via email to resolve the problem. We will reply as soon as possible and do our best to meet your needs! Suitable for outdoor sports.