Kind of useless
Made well, easy to attach to torch but why a wheel?
You can only turn the wheel less than a 1/4 turn at a time, to go from off to full power takes 4 turns. So you start the weld and then have to adjust it 4 times in order to get full power, ridiculous. I've used sliding switches in the past and they work just fine, one motion to adjust.
So again, why would they choose a wheel?