Very observant of you. It was a short period that Burr King used these when they first started offering variable speed to many of their machines. They switched to all electronic AC speed controllers like my two wheel 1000 shortly after. I've not had any issues with it, still runs as smooth as the day I bought it. Except for the 960-200 on the left (which I restored) I bought the three on the right new from Burr King at about 1 every four years. Bought each of them at the machine tool show that used to be in Santa Clara every year, buying at the show they gave 10% off. Not a lot, but for pricey machines like these you'll take anything you can get.