All batteries must be shipped with a ground shipping method.
Gaoneng GNB 850mAh 6S 22.2V Lipo Battery
Voltage: 6S / 22.2V
Discharge: 80C Constant, 160C Burst
Dimensions: 46mm(L) x 31mm(W) x 63mm(H)
Discharge Plug: XT30 Plug
I got it for 4 inch micro apex. I think 650 mah is the best option. But in any case gnb quality is good n 850 last abit longer. So you cant go wrong with :)