Vintage soviet 6K4P-V (6К4П-В) is a high-frequency pentode of improved durability and reliability designed for HF voltage amplification. It is direct replacement for the chinese 6K4 (Shuguang) tubes, which are commonly used in many chinese made headphone amplifiers and analogue of the european EF93 and 6F31 tubes. New in box tubes, directly from the old reserves. Years of production: 1963 and 1964. Tested.