Groove Tubes GT-6V6-CD R4 Duet Amplifier Tube Set Commonly used in lower wattage guitar amplifiers such as the Fender Champ, Fender Princeton Reverb, and Fender Deluxe Reverb Warm overdrive and soft distortion character Originally introduced by Ken-Rad Tube & Lamp Corporation in 1936, the 6v6 is essentially a lower-powered version of the 6l6 Hand Tested & Matched in Duets (a pair of 2 tubes) Limited Warranty Included