I am going to be looking for a used WC-115A to hook my 30A up to my Bobcat. In looking around I see two different looking versions, one with extra controls, but I can't seem to find anything explaining them. I found Miller's WC-115A manual, and it only shows the one with just one control knob.

Anyone know the difference between this WC-115A:

And this WC-115A?

Same name, but the first one looks like it must have much more functionality? Maybe just some added optional controls?