Stay warm on the trail & keep your portable electronic devices fully charged with the Thermo Charge power pack & hand warmer. Thermo Charge heats up quickly & reaches a maximum of 45 degrees Celsius. The 4400 m Ah rechargeable lithium battery provides up to an impressive 6 hours of continuous heat on a full charge. Unlike single-use chemical hand warmers, Thermo Charge is safe, scent-free & rechargeable. Just plug it into any USB (Universal Serial Bus) charging port. A rugged aluminium housing & protective silicone caps make Thermo Charge perfect for your next cold-weather excursion. Thermo Charge also delivers a full charge most smart phones, MP3 players, cameras & many other USB (Universal Serial Bus)-powered devices.