We have received stock of CRYOGENICALLY TREATED 6SN7GTB brown base Tungsol Russian reissue octal vacuum tubes. These are an exact copy of the famed NOS Tungsol type. They are very uniform in quality and have that beautiful rich life-like tonal quality that Tsol was famous for. You won't be disappointed! SOLD AS MATCHED PAIRS LOW NOISE AND MICROPHONICS TESTED.