It is a bracket which has S/PDIF I/O controller IC on it. You just mount this bracket on back plate of your chasis (it occupies one PCI slot), and connect the S/PDIF input/output cable to the header on your mobo and you are ready to run. I couldn't find a link to this but I read from a review said that the product model should be something like SD650, but not sure about this because that review is not in English or any languages I know.
You never know how stupid you are until you have done something stupid enough for you to realize it.
<A HREF="http://www.anandtech.com/mysystemrig.html?id=22996" target="_new">My System Rig</A>