The SeriTek/1eSE4 4-Port PCI eSATA Host Adapter from FirmTek adds four eSATA ports to your computer. It installs in an available PCI slot and is fully compatible with Mac OS 9.x, Mac OS X, and Windows. The eSATA interface supports bus transfer speeds of up to 150 MB/sec, making this card an excellent choice to allow you to add high-speed and high-capacity external storage to your computer.