As already mentioned, it has a charging problem. I have just charged it and it incorrectly shows that it is uncharged. You need to give it a bit of power to get it going. I contacted Crystal Audio and I am waiting for them to tell me if this is a general problem. Very bad choice, especially if you bought it to spend days away from a power source. The only positive thing about it - if it worked - would be its weight, which is one of the lowest in its category.

Extremely heavy for the terrible charging speed it provides and it doesn't even have the watts to justify it as a charger that could support my laptop. For some reason, even if I charged it all night, it might show all the lights off and not power anything until I plug it in to draw power from the charger for 5-6 seconds and it realizes it's full. I don't know if I trust a battery with such a messed-up controller.

Poor quality plastic, very heavy but you know that beforehand... the worst part is that when you put it to charge, the lights don't turn on, so it seems like it hasn't charged... so it's not reliable for knowing how much battery is left...

after about 13 months the fast charging became completely useless! afterwards, the others also stopped charging. Poor quality in the end!

First, I will mention the appearance. The plastic is of very poor quality and its weight is not evenly distributed.
And the 3 USB ports seem defective since you don't hear the familiar click when connecting the cable-device since it attaches with difficulty.
One of the 3 ports is for fast charging (not turbo/rapid).
The strange thing is that while the package includes a USB cable, the cable itself does not support fast charging.
Finally, for €49.90, I consider it expensive. With the same amount of money, there are better options available elsewhere.

As soon as I bought it, on the first charge it was good (4,000 mAh), it worked well. From the second charge onwards, it had drained. I hope I have come across a defective product and that it is not a representative example