This PCI-Express riser card allow you to utilise those slots on your motherboard you might otherwise not be able to use, and mount multiple graphics cards in more suitable positions for maximum airflow.
Powered PCI-E risers cables are essential when building a Cryptocurrency mining rig so your motherboard does not get burnt out. They are used by miners to raise the important graphics cards from their motherboard and space them out better for cooling and to enable more GPUs to be used.
It also allows you to connect your graphics card to any 1x, 2x, 4x, 8x and 16x PCI-E slots to make use of those slots you would not normally be able to use. By connecting your graphics card to the riser then to the power supply via a molex connector, you take the strain off the motherboard and prolong its life.