I bought this to replace the worn down nut on an old Hummingbird acoustic copy I had and it fit perfectly. I chose the Graph Tech brand because there is one on my Gibson J-45 and the tone of that is just great.
As with any replacements of this kind, make sure the measurements are right, particularly the width and height (if you can't get an exact size then get one that's slightly too big and you can sand it down).