The OTK17 (1P24B) is a sub-miniature valve with flying leads and the anode brought out to a top lead. It is a special quality Russian battery RF output pentode. The filament is 1.2 Volts at 0.25 Amp.
The envelope has ridges built into the inner walls and these hold the electrodes in place.
Even in this close-up no grid wires can be seen.
The Cyrillic lettering for 1P24B-B.
The ceramic spacer and the base leads.
The thin glass tube envelope is 9 mm in diameter, and excluding the base wires is 42 mm tall.
References: Observation & 3002.
Updated April 27, 2016.