The CV1064 (commercially the MU14) is a directly heated full wave rectifier. Previous names for UK Government service were: Navy - NU3, Army - AU4, RAF - VU64.
The working parts of the anodes have space for an inverted V coated filament ribbon.
The filament ribbons are welded to the supports so clearly not tungsten but possibly nickel or molybdenum.
The anodes are folded and stitched together.
There is no tension spring. The ribbon is looped over a portion of the top mica.
