Korg GT4 Guitar and Bass Tuner Tuning: 12-note equal temperament Detection Range: B1 (23.13 Hz) to B6 (1975.54 Hz) Auto Tuning Modes: Strobe Mode; Mirror Mode; Meter Mode Power Supply: Two AAA batteries (3V) included Battery Life: Approximately 18 hours (when tuner is operating with alkaline batteries, Strobe mode on, and A4 continuous input)