Nathan,

You've got pretty good eyes, those are Elite 1500 mAh NiMH 4 cell packs assembled by CheapBatteryPacks.com. I have three of them in the plane, one up in the motor box for the ignition, and two under the rudder servo for the receiver and servos. Each receiver pack has it's own switch which is plugged into the receiver putting them in parallel when in operation. I was a little disappointed to find that even with very careful pre-conditioning the packs only come up to about 1350 mAh capacity. However, they do put out a lot of current without dropping the output voltage very much..............RJ