Solar charger(Backpack) absorbs sunshine through solar cell then translate into electric energy, which will be stored in storage battery. It can charge for different specification mobile phones through corresponding connectors. It is suitable to be used (in the emergency situation when there is no electricity ) outdoors. If there is no sunshine for a long time, you could use AC travel charger or DC car charger to charge for the storage battery. You can also change full battery to the battery which is no electricity. This product is easy to operate, safe to use, convenient to take and fashionable. It is an ideal product for living and traveling.