This RCA-built 6V6-GT tube made during the late 40's features a black imprinted base, clear glass, bottom-getter and black plate. 6V6 tubes were commonly used throughout the Tweed, Brown, Blonde and Blackface Fender amps of the 50's and 60's, including the Champ, Princeton and Deluxe amongst many others.

JAN tubes of the 40's, 50's and 60's are widely regarded as the best sounding available and are really your only choice when re-tubing a vintage amp. The RCA blackplate type (like this one) is really the holy grail.