HELP! Mystery AFV part identification

[Robin Craig]

I have this odd piece.

I can describe it as heavy for the size of it, a metal (haven't tried testing for which) casting with an aperture for right eye viewing that clamps to something (likely some kind of optic) with a rubber pad all around with some numbers (forgot to scribble them down) cast into the rubber.

My questions are:-

what is it from?

was it common?

Does anyone have the real 1:1 scale vehicle this is from and need it?

Hate to bin it as I have hauled it around for 17 years and know someone must know what it is.

I'm downsizing my life and the baggage train that goes with it.

Its history is that it came from an undisclosed location with a proven CF connection in Eastern Ontario and was in a debris trail of many other AFV parts.


R