Name-brand memory cards are a safe bet for getting a quality memory card.
Now replaced with Class-10! (More fast!)
Not all SD Cards are the same. Many are "get what you pay for" from bargain sites, where cards are reconditioned or out-right hacked to fake their capacity.
That's why we've brought in name-brand (SanDisk / AData) memory cards from North American suppliers for our accessories needing SD card storage. It's a tidy little package, complete with the microSDHC card, SD-card adapter, and plastic case.
Not willing to just trust anything we read, we put a card through the "Gold Standard Tester" on a USB3 hub, H2testw v1.4, which reported:
Warning: Only 7571 of 7572 MByte tested.
Test finished without errors.
You can now delete the test files *.h2w or verify them again.
Writing speed: 10.3 MByte/s
Reading speed: 39.5 MByte/
In short, we're pretty happy with the results of these cards!