Product name: heating socksSurface material: 51% viscose, 23% nylon, 26% polyester, inner material: 100% nylonBattery capacity: 4000mAhBattery size: 15.84478.5mmBattery weight: 0.08kgCharging voltage: 5VWorking voltage: 3.7VWorking current: 800mAh-1100mAhBattery performance: -1070 battery can work normally, battery life is 80% capacity remaining after 500 cyclesCharging time: about 4.5-5 hours when fully charged (excluding ordinary mobile phone chargers)Product size: black L size: tube length 33cm, sole length 20cm, sole width 9cm;Black M size: tube length 30cm, sole length 18cm, sole width 8cmPacking list: socks*2+mobile power supply+usb line+English manual, color box packagingFeatures1. It can be machine-washed, adjusted to gentle washing, or hand-washed. Take out the battery before washing2. Super elasticity, double-layer thickening to keep warm, soft and skin-friendly;3. Using innovative spiral heating, heating wire is inlaid in the sock layer, so that the sole of the foot can be heated;5. Dual-hole usb line, one line is multi-purpose;6. High-end 4.5-5.5 hours, temperature 60-65 degrees; mid-range 6-7.5 hours, temperature 45-59 degrees; low-end 9-10 hours, temperature 39-44 degrees.