Introduction Our Amazon"s best-selling battery case for iPhone 4/4s, the DX battery case boasts a thickness of just 17mm, while also effectively doubling battery life. This technically advanced case also halves the time needed to re-charge the battery. It even allows users to sync-and-charge while the case is still attached to the iPhone. Also, made for complete protection, the DX exhibits an ergonomic hand-held fit, an anti-slip coating, and a comprehensive casing to ensure peace-of-mind. Specifications Battery Material: Lithium Polymer Battery Capacity: 1700mAh / 3.7V Dimension 120x62x17 (mm) Charging Time 3-4 hours Life Cycles >500 Cycles Box Content 1 x DX 4 iPhone 4/4S Battery Case 1 x Data Charging USB Cable 1 x User Manual 1 x Crystal Clear Screen Protector 1 x Microfiber Cleaning Clothes