A pair of WWII blc 5 + 10 x 70 B.Z. C/2 Kriegsmarine binoculars by Carl Zeiss Jena, circa 1942.
70 mm objective lenses, with variable magnification of 5 and 10 times.
The field of view at 5 times magnification is 14°, and at 10 times magnification is 7°.
This model of naval binocular was produced by Carl Zeiss Jena to be used on the gunsights of the Kriegsmarine's large warships and coastal defences, the optics are contained in the heavy duty housing to protect them from the vibrations generated by the recoil of the large 10.5 cm and 12.7 cm guns.
Literature: Militärische Ferngläser und Fernrohre in Heer, Luftwaffe und Marine: Military binoculars and telescopes in Army, Air Force, and Navy / Hans Seeger. Page: 402 - 403.