Some of the new tubes I brought home form the 2012 Charlotte antique radio meet

This is very strange, the piece inside works like a see-saw, does anyone know what it is?

I believe this one must be pretty good judging by the Oozes and Awaas emited by Mr. Jim Clark.

It's a NOS RCA 1847 Iconoscope

I was told these were German tubes used in U-Boat radios.