This is PCI-E 1X male to PCI-E 16X female extension cable. This extension cable makes the PCI-Express 16x card away from motherboard with the PCI-Express socket 1x directly in line with the socket on the motherboard. So you can install PCI-E 16X device to PCI-E 1X slot freely according to dimension and position of computer case and connect more devices easily & quickly to your computer. This extension cable is ideal for small computer & server case like 1U & 2U. - Interface: PCI - E 1X male and 16X female - Provides expansion for 1 slot 16x connnector with cable - Great for DIY project