I have recently purchased a Max Amps unlocked battery and 4S kit. I just wanted to let everyone know that for 300 bucks it does not perform. It was suppose to add 30% more power and give my bird 22 to 25 min of flight time. What I actually got was a little less then 16 min of flight time and also the drone flew much slower cruising then with a normal dji battery. Maybe other people had better results but from what I have seen this upgrade sucks.