Type 6AN8A is a triode-pentode (but here built as a triode beam tetrode) with a defined warm-up time for use on series heater chains. The pentode section is used as a video amplifier or reactance valve while the triode performs variously as a phase detector, gating valve, oscillator or phase splitter.
The RCA logo.
The open end of the pentode anode shows the two wire grids within and to the side is the bright beam plate. The cathode tube is rectangular.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 48 mm tall.
References: Data-sheet. Type 6AN8A was first introduced in 1954.