Hi! Potted is just that, a little potted motor hanging off of the back. It is belt driven and you can put it on a threadle if you would like or make it a hand crank with a little change. I have both. direct drive, not potted is generally more desirable if you want to keep it electric. If you already have a 201 there is not need for a 15-91 but $45 is really cheap. Maybe it needs to come home any ways.