I liked that this unit has more than 2 battery slots and I have 3. Unfortunately only 2 battery slots hold them tight enough not to fall when they be closed and moved. The 3rd battery must live in the case. Then again, this is the smallest case I could find! It's HEAVY, it's perfect for a Tello drone with bodyguards and it has a quality zipper and a detachable shoulder strap. So I give 4.5 - the battery does not stay in place = 3.