Firefox 11.1V 1600mAh LiPo Li-Po Li-Polymer Stick Battery 20C
[AS1492]

This battery fits in my CYMA AK-74UN (CM035). It is a tight fit but it works. This is the largest mAh battery that will fit in a top AK receiver that I know of. FYI - In case you need another battery, I also have a Tenergy 11.1v 1400mAh 20c battery with the similar dimensions (170mm x 20mm x 18mm)that fits.