The EL822 output pentode is specified for video use, i.e. 5.5 MHz and wide bandwidth DC to 5.5 MHz. The impedance is high and so is the amplification factor is high. This valve with its 6.3 Volt heater may be designed for professional video.
This exhibit was made in the UK and has the final form of the Mullard logo.
The copper supports of the control grid have small heat-sink fins attached.
There are screens top and bottom that are strapped to the suppressor grid. The copper strap can be seen top right. The cathode tube is rectangular with the working faces bowed outward.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 69 mm tall.
References: Data-sheet & 1040. Type EL822 was first introduced in 1962.