Binoculars Carl Zeiss Jena Feldstecher Vergr.=6

Magnification: 6x
Aperture (objective diameter): 18 mm
Field of view: 6.2°
Visible field of view (eyepiece FOV): 41°
The closest focusing distance: 4 m
Width: 14.4 cm
Height: 10 cm
Weight: 418 g
Production date: 1900-1901.

   On July 9, 1893, Carl Zeiss patented prismatic binoculars. Civilian models of devices were produced from 1894 to 1907 with 4x, 6x, and 8x magnification, having flat prism covers and a hinge, which was attached to binoculars’ halves with the help of screws. The objective diameter of this model is 18 mm (the earlier models had an aperture equal to 15 mm) and magnification value is equal to 6x. This model of binoculars had being produced from 1894 to 1907. Something like 14,000 of such devices were released during that period. Around 1896 a military version of such binocular appeared on the market – it was ODF95 (Offiziers-Doppelfernrohr 95), which had 6x magnification as well. This model was popular among military people and at the beginning they sold it in private, but later there were centralized supplies to German army.   
   The binocular possesses eyepieces of the so-called "2/3" transitional design (see Hans T.Seeger. Zeiss-Feldstecher, Handfernglaser von 1894-1919, Modelle-Merkmale-Mythos, pp.114-115) with the base diameter equal to 18 mm and the top prism cover width equal to 40 mm. The binoculars with such eyepieces’ design were produced approximately from the end of 1898 to 1902 (according to some data sources - up to 1905) and the mentioned eyepieces’ design was peculiar exclusively to civilian models of binoculars. 
   The binoculars frame hinge is attached to its halves with the help of 5 screws from each side (the earlier models were fixed with the help of 4 screws). The upper and lower prism covers are made of brass (the earlier versions could have been made of aluminum); the device has long “lugs” for a jugular strap, which are attached to binoculars with the help of 2 screws (the earlier models had shorter “lugs”, which were fixed with the help of one screw). There are inscriptions “Carl Zeiss, Jena. D.R.P.” on the left prism cover. D.R.P. is an abbreviation for Deutsches Reichs Patent. There is also an inscription “Feldstecher. Vergr.=6.” – “Binoculars. Magnification=6” on the right prism cover. The inscription is encrusted with the help of silver alloy. 
   The continuous serial numbering of Carl Zeiss Jena binoculars was absent at that time (it appeared only at the end of 1907); the new serial numbers were assigned according to the new model release or according to the device design changes. Therefore, relying upon the serial number "2554" and upon the binoculars design (eyepieces joint, the frame hinge fixing and so on) one can assume that the binocular was produced around the end of 1900th or at the beginning of 1901.