The Solar Window Charger uses solar panel technology and an adhesive design to stick to any window and harness the sun's natural rays to power up any smartphone. 

XD Design's Solar Window Charger is an environmentally friendly alternative to using electricity to charge a cellphone. This square solar charger comes in a silicone adhesive design that users can stick onto their window and watch as the sun's rays are converted into a power current that replenishes your phone's battery. You can even use the Solar Window Charger to charge any electronic device with a USB port.