Have the battery for a few months and it is still running, longer and better than the original from Samsung. What surprises me even repeatedly because no other name batteries do not run as long. At the last hike the original Samsung has the spirit abandoned after about 5-6 hours of continuous use, I would have been lost in the forest or catching in Geo been quite a fix. The Polar Cell keeps loose almost double the amount was just the best! , I charge the battery whenever this is 5% and clamp it at 100% again. To date, no problems. The NFC also works well. But during normal S4 I know not. From me strong buy recommendation. !!.