I bought at a flea market, what was even then (27 years ago) an old set of Zildjian hi-hats. Here's what I know:
1) 13" set
2) Both top and bottom are same weight
3) Medium thins by my estimate (They were thinner than a New Beat top cymbal, but definitely not a thin.)
4) Istanbul stamped
5) Machined cymbals, not hand hammered
I used these puppies for several years. Nice tight, crisp choke as well as slush. After I replaced them with 14" Sabian Regular hats, I turned one into a splash that uses the third hole on my Yammie tom mount on my kick drum.
Any ideas as to what this is?