Am using ambrane 10000mAh power bank from last four months. I got it from flipkart on festival season only for Rs. 499 . which I think was a great deal. Am happy that I selected ambrane power bank, because its worth every penny I payed. My phone battery drains very quickly, so I decided to try power bank. From ambrane 10000mAh capacity am getting an output of 7500mAh atleast. I can recharge my smartphone for 2.5 times. Yes , 2 and a half time I can recharge my mobile using ambrane power bank. Its wonderful , such a powerful backup device. Am getting the same result for last four months, no problem at all. Am glad that I chose this brand over others.