The PCL83 is a television audio triode output pentode from the era of VHF television in the 1950s. It produces enough output power for an average domestic environment but was designed for frame timebase and frame output.
This standard design was made by several manufacturers.
The low power triode section seen full face.
Both sections seen side view. The pentode suppressor grid support rod can be seen through the gap in the anode.
The thin glass tube envelope is 20 mm in diameter and excluding the B9A base pins, is 47 mm tall.
References: Datasheet & 1040. Type PCL83 was first introduced in 1954.