I bought mine used about 15 years ago. You can adjust the air pressure down [the collar at the base of the tool] to keep from damaging the metal below the gasket. With these tools, there is a "knack" to using it safely and effectively. Mine is starting to bypass air, so I guess I need to take it...
I have several Vulcan Flare [aka Tubing] Nut wrenches. Bought them in 1974 from my Vulcan Tool man. Yes, my Vulcan rep also went the extra mile on service. I want to thank Krusty for the history of Vulcan. Now I can fix the broken M-52A ratchet that's been sitting dead in my toolbox for the past...