male to Motherboard 20/19 Pin Box Header Slot Adapter 5Gbps PCBA
You can connect the 20pin header to the internal usb 3.0 motherboard, then connect the USB type A female to the external USB 3.0 device.
This USB 3.0 pin header adapter can be plugged to a free USB 3.0 pin header male of your mainboard in order to expand your system internally by two USB 3.0-A ports.
Thus you can connect e.g. an USB memory stick or USB-lan stick.
Since the USB 3.0-A interface is compatible to its forerunners USB 2.0 and USB 1.1, you can still use your existing USB devices.