The MESA EL-34 STR 447 offers traditional EL-34 tone & feel – urgent and aggressive – and is an excellent choice for all styles of gain, especially classic rock, alternative rock & metal. This tube is true to it's British origins with tight, focused low end, crushing midrange crunch and crystal-like highs. It's one of our favorites for authentic Brit tones. MESA power tubes are selected for their exceptional full-range tonal quality, consistency and reliability. All MESA tubes offer consistency and reliability for your tube amplifier, and certainly MESA amplifiers!