The CV1924 and the commercial equivalent TY2-125 is a power triode for use up to 200 MHz and it has an anode dissipation of 136 Watts. Mullard also advertise this valve for high power audio applications.
The B5F base with the caps on the pins to increase the diameter.
The four point anode connector and fixing support. The top of the grid is supported by a glass bead fixed to the top of the twin filament rods.
A closer shot of the glass bead and rod at the top of the filament. The filament itself is a spiral of thoriated tungsten. When powered the filament is a bright orange.
At the base of the grid assembly the twin filament leads can be seen.
The grid plate at the base of the valve, multiple connections and short(ish) leads reduce impedance.
The wide glass tube envelope is 61 mm in diameter, and excluding the B5F base pins is 107 mm tall.
Reference: Data-sheet. Type CV1924 was first introduced in 1956.