Binocular and monocular head. The binocular head is called a "Bitumi" and was introduced in 1920. It has interesting double-prism optics. The head is attached via an independent screwthread device, allowing the eyepiece axis to maintain its position relative to the microscope body.
The interpupillary distance is regulated by pivoting the eyepieces.
Carl Zeiss Jena, SN. 792. The serial number dates the binocular eyepiece to c1922.