As far as i know he never made the planned reveal.
As far as i know it´s a turning knob from a sort of vintage electronic device, but thats all i have heard.
Thanks again for your help with the threaded endpiece.
Finally i got a real one, too.
Ah, OK, just wanted to make sure I didn't miss it. No worries about measuring that end piece, glad to help. Congratulations on bagging a real one!