The CV4064 is an RF pentode and has a commercial designation of S6F33. The 'S' signifies a rugged version of the 6F33.
The suppressor grid is connected to a diode to prevent blocking when the grid is driven positive.
The structure is open with the anode being formed by two small plates that are strapped together. The suppressor grid is of a fine pitch as it is for use as a control element as well as eliminating the effect of secondary emission from the anode.
The rectangular cathode can be made out with the grid wires passing flat across the face. The control grid has copper supports.
One side of the anode. G2 and G3 appear to have the same winding pitch. G1 is too fine to see. The bright structure above the top mica is the diode connected to the suppressor grid.
The thin glass tube envelope is 18 mm in diameter, and excluding the base pins is 45 mm tall.
Reference: Data-sheet. Type CV4064 was first introduced in 1956.