Carl Zeiss Jena binocular dissecting microscope with solid, beautiful dovetailed wood (mahogany?) case and all lenses (10X lens inside + 5X lenses and 20X lenses - ocular and objective lenses). The German lens maker, Carl Zeiss, excelled at crafting precision lenses and his are considered the finest optical instruments of the time. FYI - belonged to the entomologist Dr. Ralph Durham Bird.