The CV1343 is an indirectly heated HF pentode and the base valve for the design was a modified 1937 KTZ73. The old Army service code is ARP38 and the GPO code is POVT149. Note that this valve has a 4.0 Volt heater and the later KTZ73 has a 6.3 Volt heater.
The reverse is plain zinc paint.
Looking through the top the tops of the three grids can be seen as can the cylindrical cathode tube.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 80 mm tall.