Yamaha QT1BR Features The Yamaha QT1 is a miniature quartz-accurate metronome with a built-in chambered speaker and an LED tempo indicator. The unit features 9V battery operation, recessed, bottom-mounted controls, and a 440Hz reference tone for general tuning purposes. Miniature Quartz-accurate metronome with built-in speaker and LED tempo indicator Volume control and tempo reference control with largo to presto range. Standard 440Hz tuning reference tone. In great working condition.