Practical PowerCharger with dual function: powerbank with built-in lithium battery (3500mAh/3.7V). To be used for charging most mobile devices. Input: 5V-1A. Output: 5V-1A. • Compact speaker with perfect sound. Compatible with the most popular makes of smartphones. With USB/audio cable with standard 3.5mm plug and micro USB connector. Includes instructions. The 2-in-1 PowerSound 3500 complies with European directives. When you share the PowerCharger capacity (mAh) by the ability of the battery in your mobile device (mAh), you know approximately what percentage or how often you can charge your mobile device. Each piece in a box.