I have a Samsung Galaxy SII device and this product is too big for the gs2 battery. I tried 3 diff batteries from 3 diff phone carriers for the gs2 and it was too big for each one. I didnt want to even bother with sending it back or getting a refund so I just left it as it, and uses electrical tape to hold the battery in place while it charges. Very disappointed.
It was not the right size charger but w/ a minor adjustment, I have been able to alleviate my situation, It charges well, although it takes long time, not sure if it is because of its quality or because it was not the right size for my battery.