Military cemented doublet 28mm diameter, with a focal length of 280mm and axial thickness of 8mm. In original military package marked "Lens/ Optical Instru" NSN: 6650-01-043+2200. Not sure what wavelengths it is corrected for, but not for visual. Probably designed to be used with other lenses in some military optical instrument. Coated and unused cemented doublet. Unused.
