Likely a Schönbach-made archtop guitar in a higher-end configuration, featuring a terrific, open, slightly nasal sound. The instrument is made completely from solid wood, and the neck has a rigid metal truss rod, most likely installed by one of its previous owners (in the vast majority of cases, necks of guitars made in this region were only reinforced with "skunk stripes" or other pieces of wood interglued to make it stiffer). The fretboard is made from a material, which could easily be called the king of impractical fretboard woods – ebonized pearwood. In this case, it has been carefully restored and refretted and works great.
The guitar is also marked "Klein" by pencil on both the top and back inside – possibly a name or just a production marking, we will probably never know.
