They should have the manual in a pdf file and the link to the app in text that can be copied and not in an image. Otherwise, it seems to be working correctly and I was able to test a USB charger that was giving problems and see it was defective.
Very good Quality and just 18 days delivery time to germany. WERY Important ! First I have a trouble - Bluetooth was not working ! Then I found answer on Internet. YOU have to turn GPS on ON ! Without that it will not transfer data over Bluetooth ! (Tested with Huawei P30 Pro, Huawei P20 )