Russian double triode 6N8S (6H8C) was designed for amplification of low-frequency voltage, but it usage is really universal. It is direct replacement for 6SN7, 6SN7GT and also 6CC10 tubes. Original service life guarantie: 2000 hours. Tubes were tested and are in perfect condition. Manufacturer: Foton (Tashkent). New old stock tubes made in the 60's.