The "Green Ones" look like the Bessys - from a distance.
If you look closer you notice
- the metal of the movable jaw are pretty porous castings
and sand blasted.
- the threads are
\ \
\ not like \
/ the Bessy |
/ or Gross Stabile /
/

I think the Bessy threads are called "acme thread" - much
stronger, which is why they're used on bench vises

I'm betting this is another example of you get what you
pay for. Looks similar enough - how it WORKS is another
question.

charlie b