One of the most rugged USB backups anywhere, the ZeroHour USB Battery Backup is perfect for supporting your mobile devices in outdoor, remote, and disconnected locations. Its compact, waterproof, nearly indestructible aluminum body contains over 10,000mAh of battery backup power. To upgrade to the complete ZeroHour Flashlight, purchase the Flashlight Head module anytime in the future and simply twist it onto your Battery Backup.