DIYIMING is a professional heating product technology factory with a professional design team, R&D team and production team. Every year, we upgrade our products based on technological progress and customer feedback. Using the latest technology, this heated sock is equipped with a rechargeable lithium-ion polymer battery. It has the function of controlling the heating operation on/off. It has three levels of heating, which is very suitable for cold weather activities. You deserve it! Excellent warm layer, it can transfer the heat of the heating wire to your feet. Red LED is high setting, Blue LED is medium setting, Green LED is low setting. Low setting working time is 9 hours Medium setting working time is 7 hours High setting working time is 5 hours High temperature, the highest temperature can reach 149°F. Don’t worry about not getting hot enough.