eGo T 1000mah USB battery/ passthrough 21 USD

Length of battery:110mm
Diameter of battery:14mm
Length of USB cable:1450mm

output: 3.7v

* it can work with computer directly.
* it turns on/off only by 5 clicks within 2 seconds.
* it can be charged on both end.

Simple packing

Guarantee period: 2 months