Thecard reader has a dual-slot with USB 3.0 port that can read and write XQD and SD cards. You can use USB devices at the same time. The maximum storage capacity for the XQD is 2TB and a maximum of 128GB for the SD. It offers you a versatile transfer solution between your PC or Tablet and multi-format memory cards.
Forexample, CompactFlash cards are more reliable and durable, but SD cards are cheaper and faster. So it really comes down to your preference or the type of card your camera supports - technically, there isn't much difference. What is the fastest CF card available? bawJ4.