The one port is CPU 4 Pin for plugging into a modular power supply and another port is PCI-E 6 Pin for connnecting to video cards
PCI Express power splitter cable (4 pin to 6 pin) lets you connect two ports (standard) 4 pin PCI Express power connection provided by the computer power supply to two nVidia SLI or ATI CrossfireX video cards that require a 6-pin power connection
A cost-saving solution, this PCIE 4 pin to 6 pin power cable eliminates the expense of upgrading a computer power supply for the sake of compatibility with video card systems
『Solution』Convenient solution for adding two extra PCI Express ports to your existing power supply;
『PCIe 8P female - Dual 8P(6+2)』The 8 pin PCIe female end to plug into the PCIe 8 pin male cable of the non-modular or semi-modular power supply and two 8 pin (6+2) male ends to plug into the video graphics card;
『Compatibility』Compatible with common non-modular PSUs and semi-modular PSUs with PCIe 8 pin male cable; (Note: It does not work with Fully-modular PSUs.)
『Compatibility』Compatible with 6-pin & 8-pin graphics cards from popular manufacturers such as: ASUS, ASRock, EVGA, Gigabyte, Radeon, Sapphire, NVIDIA Tesla GPU, etc. (The 8 pin (6+2) ends could be used as 6 pin or 8 pin end by sliding on/off the 2 pin.);