>>2483101It's called a 20,000 MAh external battery pack. They weigh ~8 ounces and can do multiple recharges on your phone, GPS watch, e-cig, whatever. You can do an entire month on it, as long as you aren't stupid and put your phone on airplane mode (since you aren't going to have signal anyway) and conserve battery life. An iPhone on airplane mode can last ~4 days.
