The Model 490-ST includes stretch tuning capabilities for enhanced tuning of stringed or percussive instruments such as the piano, bass, guitar, marimba, steel pan, and others. Only peterson strobe tuners respond at the speed of light to display relative tuning of any audio source to 0.1 of a cent (1/1000 of a semitone) accuracy. With the new AutoStrobe models such as the Model 490-ST, students, technicians, and musicians at all levels can utilize automatic (hands-free) note selection for fast, accurate tuning of instruments. This feature also permits real-time display of intonation to improve performance and listening skills while playing.