Replacement or supplement old Lincoln idealarc 300/300?

[kj4oll]

The manual says this about the connectors:
Gas inlet: 5/8” right-hand female
Gas to Electrode: 5/8” -18 right hand female
Water...

[kj4oll]

Thanks! That looks like a good one, and is available from my local Home Depot.

[kj4oll]

What TIG welder could I buy to replace or just supplement as a second machine?
My existing machine is a 1970’s Lincoln idealarc TIG 300/300?...