This exhibit is a Russian military specification low frequency double triode. It is closely related to the ECC83 but has an electrostatic screen connected to pin 9 and the heaters of each triode are internally connected in parallel.
The construction is designed to resist vibration and shock and the 6N2P-EB is a long life (5,000 hour) version of the 6N2P.
The English translation of the Cyrillic 6Н2П-EB is sometimes given as 6H2Pi-EB. Н is equivalent to EN and П is equivalent to PE.
The Wikipedia entry states that the gain is slightly lower than the ECC83 and most closely equates to the 5751 which was also designed for avionics. The higher heater current being used to improve reliability.
The Cyrillic lettering is 6H2П-EB. The faint logo is the Voshod factory rocket.
The triode sections are substantially built.
The two independent valves are screened by a rectangular plate across the diameter of the envelope. The lettering visible is OTK7.
The face view of one anode showing the anode side flanges for fixing.
The thin glass tube envelope is 22 mm in diameter and, excluding the B9A base pins, is 49 mm tall.
References: Datasheet & 1040. Type 6N2P-EB was first introduced in 1954.