'Matched' refers to comparing the gm test results between the lowest to the highest of the identical sections of a set of tubes. 'Matched' I consider to be within 10%. Vacuum Tubes. 'Closely Matched' I consider to be within about 5%.
Actual manufacturer Sylvania. Excellent balance between sections and near-perfect matching between tubes. From a small lot of identical tubes. Small signal (i.e. 12AX7) tubes are generally checked for noise and microphonics; power tubes (i.e. 6L6) are usually not.
Actual manufacturer Sylvania. Nominal values are given for reference on many tubes. Parcels typically arrive to most locations around the world in a week or less. Small signal (i.e. 12AX7) tubes are generally checked for noise and microphonics; power tubes (i.e. 6L6) are usually not.
This particular tube has been tested and verified for quality and performance.