WW II Mystery Lens

Description

WW II Mystery Lens.  Condition is Used.  Interesting find.  Lens was very dirty when it came in my possession.  Upon  disassembly and cleaning, the following text inscribed on a spacer ring within the lens barrel (with some typos): "May 12, 1945. Gurnsey Iland, Sark Andersy, Jersey.......".  This was apparantly several days after the liberation of Guersney Island.  On the outside below the thread the text "E.J. 5" is inscribed.
Lens is 70mm wide and 65 mm high, there are two solid glass elements sperated by a metal spacer ring with text inscribed, focal distance about 100mm, F approx. 1.4.    Weight of the lens is 728 gr (1 lb 9.6 oz).
Interesting and intriguing piece of WWII history.
It is unclear what this lens might have been used for and where it was found.  Probably not a camera, there is no aperture.  Perhaps from a night vision device?  A search light?  Did it belong to the Germans?
Original wooden box with address and sender included.
Any questions or if you have an idea of what this items might be pls let me know.