Exceptional and authentic precision "Abbe" refractometer, manufactured in Germany by the world-renowned optical company Carl Zeiss Jena, bearing the official factory serial number 20520. The Abbe refractometer is a milestone in analytical chemistry and optical physics, engineered to determine the refractive index of liquids and solids with extreme precision. This specific unit features an outstanding heavy-duty design, beautifully combining textured black lacquered finishes with pristine chrome-plated mechanical components. Lot Highlights & Condition: Authentic Markings: The instrument proudly displays the crisp, original Carl Zeiss Jena classic lens logo along with "Nr. 20520 - Germany" engraved on the main body. Optical & Mechanical State: In excellent vintage condition. The scale markings, adjustable mirror, prism system, and knurled focus adjustment wheels are fully intact and move very smoothly. Rare Historical Documentation: Uniquely comes with two rare, original vintage user manuals written in Spanish: "Instrucciones para el uso del Refractómetro de Abbe" and "Refractómetro de inmersión". Housing: The device is housed inside its original heavy wooden storage cabinet, featuring custom internal slots and a sturdy top iron carrying handle. A premier investment piece for collectors of historic scientific apparatus, Zeiss enthusiasts, or as an imposing display icon in academic and professional spaces.