Yup. Bring back memories when I see this. One of the first piece of equipment I got that's still functional.
So old, the date has faded. I have 3 same replacements for this. Two are the newer style with heatsink.
That reminds me. I have to search for the ballast that came with the Elos fixture because this Icecap was used on my very first Geisman Nova. Works so well that I decided to just keep running it even when I upgraded the fixture.