A pair Carl Zeiss Jena (blc) 10 x 80 UDF binoculars, made in 1943.
346925 UDF 10x80 blc
This binocular is an experimental model of an above water Zeilfernrohrs for the U-boat Zeieloptik (UZO). This binoculars was tested by Zeiss for UZO a torpedo U-boat aiming devices.
A document marked secret presentation by Zeiss to senior Kriegsmarine torpedo officers, dated 10th January 1944, states that such a binocular on an aiming column with 10 times magnification; 7° field of view and 8 mm exit pupil was operating on a test basis.
Literature: Zeiss Handfernglaser 1919-1946, Modelle - Merkmale - Mythos, by Hans Seeger. Page: 483