This part is a kind of semiconductor called 6P3S-E.

Function of this product has Tetrode.

Manufacturers : ETC

Image and pinout :

Some of the text within the PDF file :

Russian 6P3S, 6P3S-E = 6n3C, 6n3C-E General Tetrode, used in output stages of low frequency amplifiers. Envelope: glass, with octal base. Mass 70 g. Lead diagram General characteristics: Type Anode voltage, Volt 1 grid voltage, Volt 2 nd st 6P3S 6P3S-E 6.3 250 -14 250 6P3S 900±90 72±18 no more than 9 ≤3 6P3S-E 880±40 73±13 no more than 6 ≤ 0.5 250 -14 250 Filament voltage, Volt 6.3 grid voltage, Volt Type Filament (heater) current, mA Anode current, mA 2 nd st grid current, mA 1 grid reverse current, mkA Cathode current, mA Output power, W Mutual conductance, mA/V Internal resistance, kΩ Inter electrode capacitance, pF: Input Output Transfer Operation time, h Limited operating values: no less than 275 no less than 5.4 no less than 5.8 5.2 to 6.8 25 11±2 8.2±1.5 no more [ ... ]

6P3S-E PDF Datasheet Download