The CV1053 is a variable-mu RF pentode, with variable screen characteristics, for use as a controlled RF or IF amplifer. The frequency range of operation would be up to 30 MHz.
As a commercial valve the CV1053 can be seen as the EF39 and the two exhibits have identical dimensions suggesting a common production line.
The zinc paint has started to peel off allowing a view of the internal structure.
The adhesive makes a clear view difficult but the bright anode can easily be seen. The grids extend above and below the anode and the suppressor grid is wound on copper support rods. The control grid connects to the top cap and both inner grids are wound on bright rods.
The classic envelope is 30 mm in diameter and excluding the IO base pins it is 85 mm long.
References: Data-sheet, 1040 & 1043. Type CV1053 was first introduced in 1939.