The CV5215 is a UK government code for the ECF80. Here the retailer, Hall Electric, has added their Haltron logo. Hall Electric specialised in valve exports from the UK.
The triode is the oscillator and has to produce 5 V pk-pk signal. The screened pentode is the mixer. The valve has two cathode connections so that the two valves can be used separately if required.
The triode on the right is mounted, along the side of the pentode anode.
Here the triode can be seen to have heat radiating fins at the top of the extended control grid supports. Between the triode and the pentode is an electrostatic screen.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 47 mm tall.
References: Data-sheet & 1040 Type CV5215 was first introduced in 1954. See also1954 adverts.