Hmmm... just reread your initial post, and realized that you posted a picture of a keystroke logger, and not of the thing you're looking at

Maybe that will teach me...
In any case, are there any identifying markings on the critter? words, pictures, symbols... they can narrow down what it is.
If it's an AT to PS2 adapter, the connections will be dramatically different on both sides. I've got at least one of them, and the AT side is about twice the diameter of the PS2 side. And the pins are much larger, too.
Care to post a picture so that we can examine?