The UCL83 is an AF amplifier triode and an output pentode combined in a single envelope. The use would have been for post detector amplification and loudspeaker driving in broadcast receivers and small VHF televisions sets. The 100 mA heater is for use on heater chains in universal AC or DC mains equipment.
The wire grids of both sections can be seen through holes in the end anode walls. Normally the sections are arranged at right angles to one another. Both inner grids on the pentode have copper supports.
The triode face view. Behind the heat radiating strip is fitted to the screen grid not the control grid.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 49 mm tall.
References: Data-sheet & 1040. Type UCL83 was first introduced in 1955.