Naphos via offers the New Trent iGeek Dual-USB Output 9,900mAh Rechargeable External Battery in Black, model no. IMP99D, for $39.95 with free shipping. That’s the lowest total price we could find by $25. It functions as an emergency backup power source for cell phones, tablets, and other devices. It includes adapters for Sony Ericsson, Apple, Nokia, Motorola, LG, Samsung, HTC, and more.

About the Author