This USB 3.0 pin header 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-WLAN 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.