I bought several cards then came across this forum about how to tell which is fake and which isn’t.
For Micro SD cards I have uploaded a photo the top 4 are real legit cards…the other 2 on the bottom are fake I used this program to test them - http://www.heise.de/software/download/h2testw/50539
with all the same error messages like this:
The media is likely to be defective.
7.7 GByte OK (16332800 sectors)
16.0 GByte DATA LOST (33757184 sectors)
Details:0 KByte overwritten (0 sectors)
0 KByte slightly changed (< 8 bit/sector, 0 sectors)
16.0 GByte corrupted (33757184 sectors)
0 KByte aliased memory (0 sectors)
First error at offset: 0x00000001f2700000
Expected: 0x00000001f2700000
Found: 0x0000000000000000
H2testw version 1.3