New Trent Easypak 7000mAh Portable Triple USB Port External Battery Charger/Power Pack for Smartphones, Tablets and more (w/built-in USB cable)
This is a great portable power supply. I am a high school golf coach and I have a few key days (Sectionals and State Championships) where long-term power is critical, as I spend 6-7 hours on the course with pretty intense texting, plus work email, conference calls and the odd webinar I log into from my iPhone! I also plan on using this as emergency power during frequent power failures we get in the northeast.