Glovii Heated Insoles work great to keep your toes and feet warm and comfortable. We love Glovii insoles because of the convenient remote control that allows you to adjust temperature with the touch of a button and without having to take off your shoes. Enjoy 7+ hours of warmth during any outdoor winter activity with these amazing foot warming insoles. Remote Controlled Adjustable Size Includes Storage Case Built-in Rechargeable Battery Power Comfortable Easy to use Fits in all types of footwear, shoes and boots The product material is made by using high quality Ortholite material, which achieves a soft, comfortable, ventilate consumer experience. So it is called �Best Partners of Your Shoes� in cold winter. Built-in electronic control system uses high-frequency radio dual-channel RF wireless control, which ensures consistency, stability and aesthetics while provides us the convenience of temperature control. 4 Keys on remote control are easy to understand and use. The heating pad is made by use latest carbon fiber composite material, strong & flexible. This kind of material will not only warm the insoles, but also has health care & promoting blood circulation function by radiating far-infrared. The heating system is powered by high capacity li-polymer battery, safe & working long time. All these: high quality material & our careful work make it a comfortable, warm, easy-to-use, long-life heated insoles. ELECTRICAL TECHNICAL DATA: Voltage: 3.7V Battery Capacity: 1800mA Charging voltage: 3.0V-4.2V Power Output Efficiency:;>=98% Over-charging Protection Voltage:4.2V Over-discharging Protection Voltage: 3.0V AC ADAPTER SPECIFICATION: Charging model: CC/CV Charging temperature: 0�C~;45�C Input: AC/100-230V 40-60Hz Output: DC/8.4V 500mA*2 Built-in electronic control system with high-frequency radio dual-channel RF wireless control.