The CV455 is a VHF double triode, useful for RF stages, oscillators and frequency multipliers. The commercial type designation is ECC81. The American 12AT7 was the prototype.
The two small triodes have space between them but no electrostatic screen.
Each anode is folded and stitched such that a side wing is formed that both holds the anode between the mica sheets and adds extra surface area for heat loss.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 48 mm tall.
References: Data-sheet & 1040.