Purchased this product for my daughter who at times needs extra power if staying at school late. This product has saved allowed her the extra power to make phone calls to home later at night. THe charging cable is different than a normal iphone charger. No big deal though. Has been in ciculation for a few weeks and works well!
https://www.amazon.com/Niubity-Certified-li-Polymer-Rechargeable-Protective/dp/B0196DX6NO