A low power pentode power tube, popularized in early Vox AC30 amps. Rediscovered by Matchless amps and now currently used by nearly every tube amp company.
Quick, soft overdrive distortion, great for recording but usually too low volume for live gigs.
Product Ref: 19897
If you are trying to match your stock tube rating with the GT rating, on Fender amps, output tubes in newer amps are color coded.
The scale is:
Blue = GT 1-3 rating
White = GT 4-7 rating
Red = GT 8-10 rating