The ActionHeat 5V Insulated Puffer Heated Vest Liner is a lightweight layer designed to add warmth without bulk. Made to be worn over a base layer and under a jacket, this vest liner delivers targeted heat to the core while maintaining a slim, comfortable fit. Built with integrated heating panels, ActionHeat heated apparel is engineered to warm the core body temperature efficiently. The insulated puffer construction provides added warmth, while flexible materials allow for easy layering and all-day comfort. HOW TO USE: Charge Up- Fully charge power banks with provided charger kit. Plug-In- Connect the power bank to USB plug located in the pocket. Turn On- Press and hold touch-button control for 3 seconds. Press touch-button again to adjust the temperature. Features: Machine washable, gentle cycle Powerful Tri-Zone heating system includes 3 built-in heating panels, strategically placed on the chest and upper back to warm your core body temperature Touch-Button Control Technology (3 settings) 4 LED power indicators displaythe power bank battery life Zip front Battery Voltage: 5-Volt Material Content: 100% polyester Estimated Heating Times: High (Red): 150F - 2+ Hours Medium (White): 130F - 3+ Hours Low (Blue): 110F - 4.5+ Hours Includes: (1) ActionHeat Classic Puffer Vest Liner (1) ActionHeat 5V Power Bank (6000mAh) (1) USB Charging Cord