ltem description from the seller
1: The highest theoretical speed of 3.0 is 4.8Gbps, equating to 600MB/s, whereas USB2.0 has a theoretical maximum of 480Mbps, or 60MB/s. 2: This card reader comes without a card; it is solely a card reader. 3: This card reader can only read one card at a time and must do so sequentially. It cannot read two cards at the same time.