RARE Emil Busch 'cxn' 7x50 U-boat binoculars

An extremely rare, untouched pair the 7x50 U-boat binoculars produced by Emil Busch, Rathenow under the 'cxn' maker code - not by Carl Zeiss Jena. 
 
According to serial number studies, this binocular is 1 of only around 30 examples which are still known to survive today! 
 
Factory finished in the typical KM shade of yellow/green, this particular set retains 95%+ of the original textured painted finish. They also come complete with the original factory-fitted rubber armour and leather neck strap. 
 
The fixed-focus and coated optics on this pair still function to produce a usable and collimated image after all this time, however, they would clearly benefit from an internal clean and service if desired for serious use purposes. Note there is some very minor blooming to the objective lenses (pictured) and that the lens coatings are of the bright blue colour, unique to these binoculars that were manufactured by Emil Busch. 
 
A very rare U-boat binocular to find in any state, yet alone in such great original cosmetic condition, that would definitely be a centrepiece within any Kriegsmarine or optic collection!