BoxWave Universal Solar WindowMount Rejuva PowerPack - High Performance, Portable Solar Power 1800 mAh Rechargeable Smartphone Battery Charger (Black) Approximate solar recharge time from empty to full is 8  10 hours Strong, reusable, residue free adhesive solar panel surround for window mounting Renewable, green power source (Solar Energy) with output : 5 volts at 1 amp Micro USB input; standard USB output Available in Silver or Black color