Koutech 2-port SuperSpeed USB 3.0 PCI Host Adapter (with Low-profile & Regular Height Brackets) Two (2) external 5Gbps SuperSpeed USB 3.0 ports with up to 2.133Gbps maximum transfer rate(*1) Compliant with PCI Specification 3.0 SuperSpeed USB 3.0 is backwards compatible with USB 1.0/1.1/2.0 devices Built-in with 4-pin Molex power connector for added power source to better support power hungry bus-powered devices Supports Windows XP/Server 2003/Vista/Server 2008/Windows 7