The Intellitouch PT40 Rechargeable Tuner Combines vibration-based tuning with a Lithium Ion rechargeable battery! It is automatic, chromatic, and displays the measured pitch on a large, backlit display for easy tuning. The PT40 tuner ignores background noise - it feels the instrument's vibration instead of using sound. Works on electric and acoustic guitars, basses, violins, banjos, mandolins and more. A USB charging cable (included) enables fast charging.