I think you will find that it is the periscope shears, but with the outer casing removed. Its a conning tower upgrade/refit, something which I never ever get! After hundreds plus hours on the game I still have yet to have one.
Seriously thinking of jacking the whole thing in and going back to playing FEAR and Total war all day instead!
Sorry for the little outburst there but just had to get the conning tower thing off my chest!
