Naztech iPhone 4, 4s 1450 mAh MFi Apple Certified Portable Battery Charger Case- Retail Packaging - White Slim Profile, Extends Battery Life, Overcharge Protection LED Battery Indicators Specifications: Input: 5V, Output: 5V, Power: 1450 mAh Protection: Short Circuit/Overcharge Compatible with: Apple iPhone 4, Apple iPhone 4 CDMA, Apple iPhone 4S