Hi Vernimark,
it should be the typical Hantarex Monitor (20" or 19") like in all Zaccaria Cabs of this time.
sometimes they are called 20", sometimes 19", but they have all the same diagonal measures, depends just from the kind of measuring the complete tube or just the viewable area:-)
and they have all the typical Hantarex frame.
I can provide pictures if you need some.
If you need pictures of a clean inside starsplash (juts like new) I can provide some also.
Cu
Digi