The KT120 is a beam pentode power amplifier with a 60W plate dissipation rating enabling designs for up to 200W push-pull output.
Can substitute in existing 6550/KT88/KT90 circuits, impervious to overload, extremely reliable, long life, super-powerful tube.
Seated 113x52mmØ

"This is the most powerful audio power tube in production today. With a plate dissipation rating of 60W (compare that with the 35W of the 6550, the 42W of the KT88, and the 50W of the KT90), a pair of these KT120 tubes in push-pull configuration can deliver 150 watts or more of audio power. And when used in a vintage circuit designed for 6550 or KT88, the KT120 will deliver unbelievable amounts of clean headroom, low end rumble and dynamic punch all without overloading. The glass of this tube is a full 1/2" taller with the internal plate structure 3/8" longer than its nearest KT88 cousin. The internal control grid cooling fins are twice as large as the KT88 adding to the amazing performance of this tube. This particular tube draws between 100mA (.1A) and 300mA (.3A) more filament current than a standard KT88, so check with your amp manufacturer to insure you have the additional filament headroom to power these tubes. This new KT120 is the steamroller of audio tubes, prepare to be flattened. " Tubedepot