Apparently chris75 has drank the UL/CB manufacturer kool-aid. They don't like to call them testers, because then they might have some obligation to make sure that their product actually works right with them.
Basically, when they come out with a new CB/outlet that fails with common testers because the tester might not produce the same test conditions they used, instead of fixing their product, they just call the tester an "indicator" and say to use the internal test button...
It's a big cop-out on the manufacturer's part.
This is what I was looking at on the Hubbell web site: