Prolix Power iPhone 4/4S Protective External Battery Case - Fits all versions of iPhone 4 - Aluminum (Silver) Prolix Power 1800mAh Bulit in Battery Charger Case will effectively double the battery life for your iPhone 4/4S Featuring a low profile and slim design, you will forget you are carrying extra power on the go Cut outs for all the iPhone 4/4S features, use your iPhone without removing it from the case The case features a MicroUSB input port and lightning output port, and can be charged together with the iPhone 4/4S (Micro USB Cable included) The Prolix Power comes in 3 colors: Silver, Blue, and Rose