The ZeroLemon SolarJuice 20,000mAh battery pack is dust, water, and shock resistant. It be charged via a micro-USB port at up to 2.1A or via solar at 0.2A. The solar cell is rated at 1.2W which provides the 0.2A charging rate. The portable charger also features a flashlight which is turned on by pressing the multi function button twice. The multi function button can also be used to determine the charge vie four LED indicators, as well as turn the charger on and off. It features two USB-A charging ports with one rated at 1A and the other rated at 2.1A.
The SolarJuice 20,000mAh portable charger is slightly larger than most chargers of this capacity but I believe this is because it has to house the solar panel as well as be water tight. Even though it is larger than most of this capacity, its weight is on par with the others. I had no problem charging the device at 2A which took about 16 hours to fully charge. The device was able to charge an iPad at 2.3A while also charging my Nexus 6 at 1.1A. Both ports were able to output more than they are rated at which is awesome. As for the solar charging, I believe it is more of a gimmick and is really only for emergency use. That being said, if you are someone that goes camping or is off the grid for an extended period, it may work very well for you to maintain the charge simply by clipping the charger to your backpack with the supplied clip. Since the solar charger can only charge the battery at 0.2A it would take roughly a week to fully charge the device from dead.
The ZeroLemon SolarJuice 20,000mAh portable charger is a well built device that outputs more than it is rated for and is capable of taking some abuse. Combine this with the ability to solar charge in a pinch and the three year warranty, and I have no problem recommending this portable charger.
If you are interested in purchasing the ZeroLemon SolarJuice 20,000mAh portable charger it can be found here.