All the batteries are the same 3.7v--- -401,510,601,801,901 and the SD but with higher mAh except the prodigy V1 it has two 3.0v and stepped down to 5.0v and the GG has two 3.0v witch makes it 6v
mAh is measured at 500mAh of continues battery voltage for one hour
SD uses a 1000mAh bat at...