Slow, small sized device is modified on Firmware level to report larger space. Speed is also not what is on label.
e.g.
You will get 8GB drive advertised as 512GB.
Problem thought is that windows see it as 512GB and when you write it to you don't realize you are losing data which makes it worse as it won't tell you it is full, just overwrite data. So as backup device you basically lose your backups and only realize it when you want to get it back.
I looked at so my reviews on these cheap cards and saw they have high ratings like 4.7 but there are always 1 star ratings reporting them as fake. However somehow Temu still allow them to remain to be bought.