Lithium Polymer or LiPo battery, they have a much higher discharge rate (due to a lower internal resistance) than regular NiCad / NiMH battery which results in turning motors much faster and/or with more torque (as they draw more current than normal).

Generally, a 7.4v LiPo turns a motor about the same as a 9.6v conventional battery; an 11.1v is on par with a custom 12v+ battery. Running an AEG on the powerful 11.1v LiPo will most definitely increase the your AEG's motor output, but will result in more rapid wear of internal parts.

Dimension
12.3cm X 2cm