2-Port PCI-E PCI Express 19-pin USB3.0 4-pin Connector Low Profile B1R3,USB3.0 4-pin Connector Low Profile B1R3 2-Port PCI-E PCI Express 19-pin,0 ports) for standard desktop PC, Supports PCI Low profile, Built-in with 4-pin Power Connector for added power source to better support power hungry bus-powered devices,Extend with 2 USB 3,0 downstream ports and 1 USB3,0 19-pin connector(can expand another two USB 3.B1R3 2-Port PCI-E PCI Express 19-pin USB3.0 4-pin Connector Low Profile.