SMART HEATING ZONES: Rechargeable electric thermal underwear , back and waist both heating,which can relieve shoulder, waist and abdominal discomfort. using carbon fiber heating technology, temperature controllable. SAFETY PERFORMANCE: Built-in carbon fiber heating sheet, 3 seconds fast heating and can up to 65C. Stable performance, safe and reliable, environment friendly, soft and comfortable.Three-speed adjustment with one-button switching. Long press for three seconds to open or close. USB CHARGE: The electric Thermals Underwear uses a USB interface. A 10000 hp mobile power supply can cause the thermal Underwear to generate at least 8 hours of heat(No included). THIN LIGHTWEIGHT THERMAL : feels like second skin, with four-way stretch and gives you the needed warmth without thick or heavy layers. The suit can be repeatedly washed without shrinking. Machine wash, dries quickly. APPLICATION: Warmest Top and Pant Sets makes your favorite cold weather activities more pleasant. Whether you are hiking; biking; hunting; snowboard; ski; camping or other outdoor sports; winter activities and even sleeping Thermal set keeps you comfortable. NOTE: power bank not included, Tops are hot in zone 16, pants are hot in zone 12