Popular Science by Celestron Elements ThermoCharge 3 Dual Pack is a must-have 2-in-1 tool that everyone needs: a long-lasting hand warmer that provides up to 4 hours of continuous heat and a portable power bank to charge your personal electronics. This special edition includes two ThermoCharge 3 units to keep you and a friend warm-or one for each hand if you're in very cold conditions!Whether you are enjoying a brisk morning walk, camping, stargazing, or just sitting on your front porch, the ThermoCharge 3 will provide heat and power to keep you going. It also makes a great addition to your adventure gear or emergency kit.Popular Science by ThermoCharge 3 will keep your hands toasty warm with a maximum temperature of 113degF. It features an ergonomic design that provides maximum contact with your hands, keeping you warm and comfortable. Unlike single-use chemical hand warmers, ThermoCharge is scent-free and its lithium-ion battery can be recharged again and again.When you need to top off the charge on your smartphone or tablet, just plug it into the 7.5V-2.1A charging port. You can even use the charging and hand warmer functions at the same time.