This is one of the best batteries I've used and it fits perfectly in my Echo1 P90 compartment.

This has seems tons of use and abuse and it can still get my P90 shooting over 35 RPS combined with a G&P M160 motor and 13:1 SHS gears. When compared to my Turnigy 11.1v 2000 mAh nano-techs, they actually perform a bit better! Only issue is that I can't for the life of me track down any more GE power batters.