PFR The standard acoustic bridge is adjustable. But usually only by a guitar tech or luthier. The point is that once the guitar is stable and properly set up there is no need for adjustment unless the string gauge is changed. Ideally then a new saddle is fashioned and if it is decided to go back to the original gauge the original saddle is put back. I long ago found my ideal string set and also learned to make my own saddles.

All the famous name flat top adjustable bridges have proved to be unpopular, heavy tone suckers and discontinued.