This SanDisk UHS-1 TF Card is in good quality.However, it is not working as fast as the Class 10 standard. For operating a series of 4KB files, it can only read at ~2.6MB/s and write at 1.5MB/s.Compared to the SAMSUNG UHS-1 microsd, the SAMSUNG UHS-1 card can at least process 5MB of 4KB files per second, either reading or writing. For reading/writing giant files, This Sandisk card can reach &#62;30MB/S for reading and &#62;15MB/s for writing, which is acceptable for this price, but still a bit lower than SAMSUNG.