Slow or defect
I bought two of these at KTech aka IMPC.
One was much slower than advertised:
with 57.7x 1GB test data (optimal)
Writing speed: 35.7 MByte/s
Reading speed: 38.9 MByte/s
The other one unplugs after the first 1.5GB of data written reproducible.
It works in a pure USB 2.0 port though.
KTech aka IMPC had them tested at their supplier and offered an refund for the pure item costs afterwards. The shipping costs back and forth were my entry costs in the lottery for a product that works as advertised. A bit slow but a friendly Service indeed.