La Filotecnica Salmoiraghi Cased Sextant, ca. 1940

Description

A La Filotecnica Salmoiraghi painted brass sextant with original case and key, Milan, Italy. The sextant dates from around 1940,  based on serial number and date on the battery of 3-40. The portable navigational device with black painted brass frame and silvered arc scale, fitted with 6×30 monocular lens and 10×17 inverting telescope (powers are estimated; neither is marked), mirrors, and micrometer thimble, wired for battery power, with maker's marks and serial number, including mahogany lined fitted mahogany case.
May be missing a lens on the sighting tube (no way to adjust for focus), and it is missing the shade for the sighting tube. Missing the light bulb. Slight oxidation of the mirror, and significant haze inside the monocular lens. A knob on the underside of the index arm is partially broken.
Surprisingly, the battery showed 2.8 volts on my multimeter!
No indication of certification. Given that Italy joined WW2 in June, 1940, this may have been set aside while the military was involved in other matters. Condition of the case suggests that it was not put into general use.