Simply charge this iPhone 5 Case Charger from your PC using the provided USB Cable until it is full; then simply charge your device whenever you need power. Rechargeable Lithium-Ion 2200mah battery pack increases energy efficiency. Great for traveling and long flight - for your iPhone 5 Compact size allow easily carry in bags, pant pockets, or shirt pocket 4 LED battery meter displays remaining power level. Super thin and light, it is the most thin and light battery cover for iphone 5 in the world !