ORIGINAL: Wolfpackin

Any 3S 11.1V battery will work.
mAh is capacity so the 2200mAh will give you longer flight times.
The only thing to be concerned with is as the capacity goes up the battery is usually bigger and heavier.
Many people are using the 2000-2200mAh batteries in the B400. Just watch the weight and dimensions.
The bigger batteries are a tight squeeze under the canopy.