I have one set that worked great on my 4-20. It works great on my old ProMelt as well, and the adapter is now clamped to the top of the mounting post for the mold guide, where a binder clip on the bar holds my PID probe (just a hack to use the superfluous guide part on the old model ProMelt - the new ProMelt doesn't need it, and from the pictures I've seen doesn't have room to mount anyway).
Short version - highly recommended, would buy again ;^]