The AutoStrobe 590 is THE preeminent mechanical strobe tuner for tone generation and metronome facilities. It combines both input instrument tone and audio standard reference tone at the output for simultaneous visual and audible tuning along with exceptional intonation training! The 590’s key features (automatic note tracking and audio tone generation capabilities) make it a favorite in the classroom, at the factory, or backstage. And as usual, only a Peterson can respond at the speed of light to display relative tuning information extracted from any audio source down to 0.1 of a cent (1/1000 of a semitone) accuracy! Finally, utilize automatic (hands-free) note selection for fast tune ups of instruments. Proudly made in the USA.