Compact Flash interface for downloading photos. It's $84.50 at geeks.com
You do need to add a hard drive. It is designed for the hard drives used in portable computers. Mine is a 30gig drive. I download photos to it on the road, and use at for temporary portable storage at home.
I'm trying to decide between hard drive (HD) and DVD burner portable storage devices that I can take on trips to download Canon RAW files from my CF card. Once deciding between HD vs burner, then I need to select one with extra batteries. Any suggestions or comments are welcomed.