USB-C is a future proof, reversible and high power connection that works both as power input and output. Always charge your mobile devices and the Solartab C itself at maximum speed.
Including USB-C devices like Google Pixel, Nexus 5x and 6P, HTC 10, LG G5, OnePlus 2 and 3 and even the Macbook. As well as all your regular USB devices, like the iPhone 6s.
https://www.youtube.com/watch?v=msCWQw4OdmU