The SATA II PCI Express Card with 2 eSATA Ports from LaCie is an easy way to give your computer speedy eSATA connectivity. Compatible with Windows and Mac systems, this card fits into an available PCI-E 1x card slot on your computer and features two eSATA ports. With these ports, you can connect external devices that also use eSATA ports. Because this card is SATA 3Gbps compliant, you can transfer data between your computer and connected external devices that are compliant at a top speed of up to 3Gbps or 300MB/s. In addition, this card is also compliant with SATA 1.5Gbps if connecting to devices that are compliant with that older SATA interface. Because these ports are hot-pluggable and unpluggable, you can connect eSATA compatible external devices without having to restart your computer each time. The card also supports RAID 0 and 1, Native Command Queuing, port multiplication, and PC bootability. With this simple-to-use card, you will experience fast data transfers, great for use with your supported external hard drive or RAID array.