The size is just large enough to fit in a 19" rack. It's also possible that I don't have what it goes to.
Here are more panels to puzzle over: http://imgur.com/a/8nJ5I In related news, I am missing the bottom panels for an RK05J. Never got it with the unit I picked up, nor the cards. I've been slowly accumulating cards, but I'm not quite there yet. It's in otherwise nice shape. Not sure what happened in its former life. Kyle