I switched over to Ultra-dots, when Trijicon, quit supporting/relamping Armson OEG's. I had to have a one inch tube to fit a expensive scope mount on my compound bow. Rings were not removable. Ultra Dot was the only option...........every other one's were 30 mm tubes or some other oddball metric designation. The rheostat never got set past the lowest setting, unless, I was facing directly into full sun.............hardly ever. Even at the lowest setting, it was too bright for dawn and dusk. When I switched to an X-bow, I didn't put an Ultra-dot on it. I went with a Trijicon Reflex.
I have half dozen of the Armson OEG's, from the early 80's. They can't be relamped but they all still work, except during extreme low light conditions................so they are relegated to plinking, not hunting or personal defense.