Old F20 Preheat Aquarium Light

Here's an old F20 preheat aquarium light (don't know the age though i'd guess at least 70's)

This originally had one of those "push & hold to start" switches, but i added a starter because when i had this in use, the tank lights were on a timer.

Note how the ballast is mounted in-line on the cord rather than in the fixture.