Mediasonic 2 Ports USB 3.1 GEN II (10Gbps) PCI Express Card 1 USB Type C and 1 USB Type A Port (HP1-U31AC) (USB 3.1 A + C) External 2 Ports USB 3.1 (1 x USB Type C and 1 x USB Type A Port), Support All USB 3.1, USB 3.0, USB 2.0, and USB 1.1 Devices, USB 3.1 SuperSpeed+ support maximum transfer rate at 10.0 Gbps per port, backward compatible SuperSpped 5.0Gbps, HighSpeed 480Mbps, FullSpeed 12Mbps, and LowSpeed 1.5Mbps. PCI Express 2.0 / 3.0 x4 Lane Gen2 Interface, Compliant with Intel Extensible Host Controller Interface (xHCI) Specification 1.1 Compliant with PCI Express Specification 1.0, 2.0 and 3.0, Compliant with Low Profile PCIe Form Factor, ready for all size of PC cases 5V USB bus power directly from PC power supply via 15 Pin SATA to 4 Pin Molex Power Cable, Suggest using In-Box driver on Windows 8.1 / 8 for USB Attached SCSI (UAS) performance