Stay warm on the trail and keep your portable electronic devices fully charged with the Thermo charge power pack and hand warmer. Thermo charge heats up quickly and reaches a maximum of 113 degrees Fahrenheit (45 degrees Celsius). the 4400 mah rechargeable lithium battery provides up to an impressive 6 hours of continuous heat on a full charge. Thermo charge delivers a full charge most smart phones, Mp3 players, cameras and many other usb-powered devices. Unlike single-use chemical hand warmers, Thermo charge is safe, scent-free and rechargeable. Just plug it into any USB charging port. A rugged aluminum housing and protective silicone caps make Thermo charge perfect for your next cold-weather excursion.