Matched pair of high quality beam tetrodes 6P3S-E (6П3С-E) used in output stages of low frequency amplifiers. Russian equivalent of the 6L6GC and 5881 tubes. Fully tested on RoeTest V10 precise tube tester and matched in pairs. High quality, long life - E tubes (not less than 5000 operating hours under prescribed conditions), gold plated first grid. New in box (boxes may wear some longer storage marks). Year of production: 1976.