AnkerDirect via Amazon offers the Anker Astro E4 1,300mAh External Battery Power Bank in Black, model no. AK-79AN13K-BA, or White, model no. AK-79AN13K-WA, for $39.99 with free shipping. That's $6 under the lowest total price we could find for a similar 1,300mAh battery pack elsewhere. It features dual USB ports for simultaneously charging two devices, four status LED lights, flashlight, lithium-ion battery, connective adapters, and USB cable.