6S15P (6C15П) is an ancestor of the more common tube 6S45P-E. Like the 6S45P-E, also the 6S15P may replace the well known WE437 tube. These tubes were produced in a small scientific town of Fryazino nearby the Moscow. They have been produced until year 1969 and then replaced with the already mentioned tube 6S45P-E. High quality tubes with gold plated grid. All available tubes are new in box and tested. Year of production: 1966.