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 use e.g. connect 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. Based on the mainboard, both USB ports are aligned upwards and stacked.