Case for Part Of Noise Generator 4423

[Hannahob]

Hi! My first post I bought this empty case the other day because it looked interesting. However, I can't find much about the piece of equipment it would have held. There was a search result on a Land Rover website referring to a cable for it.Anyone know anything about what the equipment would have looked like, please? And who would have used it, please? I'm assuming it's post-WW2 because it looks in relatively good nick. I'm also wondering whether it's genuine, or something someone's knocked up as a prop?

Thank you!