Most of portable chargers are just additional mains charged batteries. However, using solar energy E-Saving charger will come to the rescue at any minute.
The group of Korean designers Gan Yexin, Huang Zhicong and Wang Zihua equipped their charger with flexible solar sheet. In case of necessity a user can roll it out and charge the E-Saving. Indicator on the front panel shows current level of battery charge.
You can use it to charge any device with USB port : there are three of them on the front side.