1,LED indicator 2,accurate 3,easy operate 4,high quality 5,deliver on time Item of tuning: Guitar,bassA4 Frequency: 440HZPick up: "MIC" and " CLIP"Tuning mode: AutomaticColor: BlackBattery: AAA size battery x 2Size: 92 x 53x 17mm mini digital Guitar/bass Tuner with LED