1954 Klipschorn Sound Reproducer value???

Hello. We bought a house that had this speaker in the basement. We're interested in selling it, but I don't know much about them. I know it's rather rare and a pretty special piece. Would any of you experts tell me what you think it's worth, please? I'd greatly appreciate it!

Here is a link to some pics:

https://photos.app.goo.gl/bCxfMVesYvNbGD636