Adds two eSata ports to your laptop to allow you to transfer data to external hard drives/optical drives.
I found this by accident when browsing around for USB 3.0 gear. Normally these eSata expresscards cost £20 or more, as far as I can tell.
I know that in theory eSata isn't as fast as USB 3.0 but it is a cheap way to step up from USB 2.0 with a decent transfer-speed increase.
Handy for copying data from external drives.
I hope some of you find this useful.