Operation is simple and works flawlessly.
Only the fact that no charger is supplied is somewhat disadvantageous. But since the "ordinary" mobile phone charger with Micro-USB port and mind. 5V output voltage * is appropriate, also provided this is usually not a problem.
Overall, highly recommended!
* I noticed that the battery pack is not fully charged at too low a charge voltage. Three LED lights do not go on like this. Therefore it should be ensured that the power supply used can also provide the charging voltage required before wrongly a defect is suspected in the battery.