There is no LED indicator indicating how charge is the battery but I consider that it can charge a laptop once (which was the case), so I loaded on my computer until the light turns from red to blue. In short, no complaints. It is simple to use.
One downside to my taste which explains the 4 stars: The battery is supplied with a USB cable type> three shots: micro usb, iphone and samsung tablet I guess. I do not see much use because quite frankly, I have neither Samsung nor the iphone so I did not want to carry it three in a cable with me (can be a selling point but it's gadget ). So I use one of my own USB cables> Micro USB which fixed the problem.
In short, a good small battery to help you out and keep you dry down, a good choice.