🔔Unisex Outdoor Battery Powered Heating Socks with rechargeable Li-ion batteries, equipped with 3 heat settings for adjusting temperature. Heated socks are made of thick fabric cotton to provide enough power do long working hours & cozy temperatures can keep your feet warm and comfortable all day long. Great fit for any indoor outdoor activities. Compared to other similar products, it adopts an innovative spiral heating electronic control system, the heating wire is embedded in the sock layer, allowing for all-round heating of the foot center, dorsum, toes, and sole. AITREE Electric Battery Operated thermal heated socks are great Birthday/ Halloween/ Christmas/ New Year Surprise gifts for your parents, lovers, and friends! Features - 3 Heating Levels Heated Socks - Low-temperature:102⁰F-110⁰F, 8-9hours - Medium-temperature:115⁰F-135⁰F, 6-7.5 hours - High-temperature:140⁰F-150⁰F, 4.5-5.5 hours 🏂 Large Capacity Battery Heated socks includes a pair lithium-ion rechargeable 3.7V 4000mAh batteries. 🏂 360° Surround Heating Socks Equipped with far infrared heating elements, these socks provide rapid warmth to your entire foot. 🏂 Machine Washable Heated Socks Can be hand-washed or machine-washed. When machine-washing, remember to unplug the power source. 🏂 High-quality Material Heated Socks Made with high-quality materials, breathable, moisture-absorbing, and warm. 🏂 Size Selection Medium (M) is suitable for US men's shoe sizes 5-9/women's shoe sizes 6-10. Large size (L) is suitable for US men's shoes sizes 10-12/women's shoes sizes 11-13. Specifications: Product Type: Rechargeable Battery Heated Sock Material: 78% Cotton, 20% Polyester, 2% Spandex Color: black Battery Capacity: 4000mAh Charging Voltage: 5V Working Current: 800mah-1100mah Output Voltage: 3.7V Battery Size: 1.5 * 4.4 * 7.8cm Charging Time: 4 hours Battery composition: lithium battery Battery on / off mode: Power on: double click the switch to turn on the power Power off: press and hold the key to power off Gear adjustment: click after power on to cycle gear shift Package Contents: 1 Pair Electric Heated Socks 2 x 3.7 V 4000mAh Li-ion battery 1 x Dual hole USB cable 1 x Users manual If you have any questions about quality or size, please feel free to contact us, AITREE heated socks will assist you within 24 hours.