The CV4079 has a commercial equivalent in the GEC A2293 and the prototype was the VX3208. When fitted with flying leads it is called the CV4038.
It is a low impedance triode with an anode dissipation of 15 Watts designed as a series pass element in stabilised power supplies.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 62 mm tall.
Reference: Datasheet. Type CV4079 was first introduced in 1957.