A 12AX7, one turn. Two triodes share the bottle, with a mica at each end. The getter ring sits above the top mica, under the silver it left on the dome.
A 3D render from Amp Tech Simulator. amptechsim.com

A 12AX7, one turn. Two triodes share the bottle, with a mica at each end. The getter ring sits above the top mica, under the silver it left on the dome.
A 3D render from Amp Tech Simulator. amptechsim.com