6N13S (6H13C) is a double triode, which was originally designed for operation in electronic stabilizers. It is direct replacement for 6AS7G and also russian 6N5S (6H5C) - military version of the same tube. Service life guarantee: ~ 1000 hours. Maximum weight: 90 g. Tubes are directly from the factory packing. Produced in the Svetlana, St. Petersburg factory during the 80's. OTK stamp.