The Energi battery pack is a small, powerful charger. It is slim, yet has enough juice to more than double your phones battery capacity. It uses battery cells certified at the highest level. This ensures users can the product for years with minimal degradation and without worries about safety. The Energi battery pack also has a built-in arm, meaning you can leave your cables at home. Use the built-in arm to charge your device when you're on the go. You can even charge two devices at the same time! Never lose track of how much power you have left with the LED indicator.