USB keys are so ubiquitous and cheap that manufacturers are forced to riff on form factors and, most importantly, names. The iDisk Diamond is just a chunk of flash memory attached to the leads of a USB key sans metal cowling. Yeah, I just made up all that terminology, but you kind of get the gist of things from the picture: it’s a USB key without the case.
128MB at this point, more in the future, and this will definitely get lost in your digestive tract if you eat it.