yeah I've seen this when I was like 5. Its an old machine (well, this one isn't a machine) whereby the weight hangs from a (steel) cable connected to a fixed rolling bearing with handles. You just roll the thing up and down - really burns the forearms with no strain on back from holding heavy weight whatsoever.
Darth, genetics does count alot unfortunately. Take me, I hardly train legs these days and they still retain good mass, shape, definition, and even size. Arms, on the other hand, I hit twice a week. They're ok...but if I skip just 2 weeks - they deflate conciderably. Whats that other than genetics?