uNu Power DX PLUS External Protective Battery Case for iPhone 4S and 4 2400mAh - MFI Apple Certified (Matte Black, Fits All Models iPhone 4S/4) Highlighted by its lightweight, ultra slim design, the DX case measures an impressive thickness of just 17mm. Featuring the strengthened polycarbonate housing, raised lips around front screen, and form fitting design, the DX will provide the most comprehensive protection to your iPhone 4/4S. Equipped with a 2400mAh battery cell the DX almost doubles the life of an iPhone 4/4s. The additional power yields six hours of talk-time, 35 hours of music playback, and a hefty 300 hours of standby time. Awarded the prestigious Made for iPhone certification, the DX has gone through extensive testing and quality assurance to ensure reliability. In fact the DX has been proven to give quality power even after 500 full recharging cycles! Made with state-of-the-art technology, the DX allows users to use any function button with case one, sync and charge with the case equipped, and visualize current battery levels (of the case) via the sky-blue 4-LED battery level indicator. The DX case is backed by the 1 Year worry Free Warranty with Coverage on any factory defects. It also comes with free Gifts including: 1 x High Quality Screen protector, 1 x Micro Fiber Cleaning Clothe, 1 x USB charge & sync cable.