help please Do you know what this is

This was given to me a while ago supposedly of a crashed Lancaster. Any ideas please. One side has been severely flattened. I have asked on other forums and the Engineer at BBMF, and several organisations. So far it has been a blank. the drawing shows lots of numbers including Government ones

Its sits on a wooden plinth in my lounge and my dear wife polishes it every so often. It is brass but several different colours, It is about 3 inches long.

I have had it for about 10 years and would love to know what it is