Mediasonic USB 3.0 PCI Express Card HP1-SU3 Support USB transfer speeds of low speed (1.5Mbps), full speed (12Mbps), High Speed (480Mbps), Super Speed (5Gbps) Compliant with PCI Express Base specification revision 2.0 OS support: Windows XP / Vista / 7 & 8(32/64 bit) Note: This item does NOT support Mac OS Interface: USB 3.0 SuperSpeed 5Gbps External Port: USB 3.0 port x 2 Output Voltage: DC 5V Dimensions: 121.5mm x 80mm x 21mm (LXWXH)