The 6P9 is the English name for this Soviet metal output beam tetrode. The Type on the envelope is in Cyrillic 6П9. The 6P9 is describes as being designed for power amplification in broadband amplifiers. It is vibration and impact resistant and has a guaranteed service life of 2,000 hours. This exhibit is unused.
The metal envelope has been pinched in at the top, presumably to hold the internal structure rigid. The letters are OTK.
The rest of the envelope is plain. Construction differs from the American metal valves, as one would expect, the envelope tube is fixed to the base assembly and the seam is visible.
The thin glass tube envelope is mm in diameter, and excluding the base pins is mm tall.