The PCL84 is a television triode and output pentode mainly for use as a video output stage. For this wideband amplifier service a high mutual conductance is required and here the gm is 9.5 mA/V
The triode on the left and the pentode at right angles to it on the right. It can be seen to be a true pentode by the three grid support rods extending beyond the mica supports.
The pentode with glass discolouration that looks like a copper deposit. The wording is Made in England.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins it is 59 mm tall.
