rob wrote:

what's a auto darkening welding mask, and how does it work.
I am presuming that it somehow switches from a see through state to a black
state when flashed by the welding torch. Right ?????
rob

That's exactly what it does. It's an LCD (like a digital watch display).

The big advantage is that it means you don't have to [a] hold a mask to
your face or [b] flip a mask down. So you can use your hand to hold
stuff, and keep your head still.

--
Grunff