I was just given an Xbox360 (I'm new to Xboxes) and bought this to use a thumbdrive instead of the over-priced 64MB XBOX 360 memory unit (a 64MB thumbdrive is only $10). It didn't plug into my Xbox 360.
Apparently in going from the XBOX to the XBOX 360 Microsoft changed the memory unit plug so you can't use your old memory units. Pretty slimy eh? What do you expect from the company that invented the "charge your customers to fix existing bugs" philosophy.
I'm sure this works for the Xbox though. It looks like good build quality, and frankly I'm amazed more people don't buy it.