Eyestone acoustic guitars are handmade Leonhard Augenstein. Augenstein has designed two standard models - the model A & model B. Augenstein has modified the details and form of traditional guitar designs - the most significant change is to the traditional bridge designs, which has became the new eyestone-bridge. German professor in acoustics Mr. Juergen Meyer established the basis for this bridge design in the 1980s with extensive research. This bridge has a striking and unusual shape - extending to the soundhole.