About the same size as a smartphone, the Tovatec Solar-Powered Battery Charger can store enough energy to recharge a typical smartphone six times. It's equipped with two 2.1-amp USB Type-A ports, so you can charge two devices simultaneously. Its three folding solar panels can generate 5.5 watts and recharge the charger's battery in eight hours, or you can plug it into an AC power source via the micro-USB input and recharge more quickly. The battery has a capacity of 16,000mAh, with an LED indicator that displays its status. Measuring 6.1 x 3.3 x 1.1" and weighing 14 ounces, the Solar-Powered Battery Charger is easy to carry in a pack, pocket, or bag.