Groove Tubes GT-EL84-S Medium Duet Amplifier Tube Once the most common low-power pentode power tube, the EL84 was popularized in early Vox amplifiers Developed by Phillips in 1953, the EL84 was originally used in tube radios before being adopted by Watkins and Vox amplifiers This tube features quick, soft overdrive distortion, and it's especially great for recording applications with low-power amps Hand Tested & Matched in Duets (a pair of 2 tubes) Limited Warranty Included