ROCKFIRE INTERNATIONAL™ Power Bank is made of Sturdy Aluminum Material & A 4000 mAh lithium polymer grade A battery!  This product is made to last, and offers a massive amount of extra-long lasting power supply for most cell phones and devices with a USB/Micro USB input. 
 
Product Details:
 
Aluminum material.
0.375" H x 2.625" W x 4.75" L size.
4000 mAh lithium polymer grade A battery.
Allows you to charge two devices simultaneously with a total output of 5V/2A.
Input is 5V 1000mA, outputs 1:5V 2000mA and output 2:5V 1000mA.
Compatible with devices with a micro USB input.
Includes a USB to micro USB charging cable.