you mean the pk-a? https://russianoptics.net/PK-A.html
i do have a replica which externally looks very similar to the pic @Asomodai dropped (at least in terms of finish quality), although it's some rando chinese brand.
pretty nice externals but internally it's the same setup as (insert £10 chinese red dot here) and there's quite a tint to it, although that said it's never shifted zero on me (on an aeg, doubt it'd take a gbb). of course parallax free is a term most airsoft sights don't understand.