RWA 7.4v 1000mAh (20C) AK Stick Type Lipo Rechargeable Battery (Small Tamiya)
RWA likes nothing more than to push beyond the current bar setters and make something of even better quality and the 7.4V batteries will surely do the job. They can be used in airsoft aegs, RC cars and plays as well as transmitters. Make sure the compartment space is large enough if you're thinking of placing them in between the outer barrel and handguard. And now we finally have something for the confined spaces in AKs too!
The batteries come in forms of Small Tamiya plug, dimensions are 9 by 13 by 165mm