JOYO JM-91 Mini Portable Multi-functional Vocal Metronome 1. Mini size with clear loud sound for easy and convenient use. 2. You can stand it up using the back rest, clip it onto a music stand, wrist it on your waist. 3. 12 accurate syllables for tone generator, 5 built-in tones. 4. Editable stored 9 parameters, fast switching by one button. 5. LCD screen to display working information, you can adjust tempo, beat, rhythm, prog, sound, vol. 6. Built-in rechargeable lithium battery and convenient USB adapter to ensure long duration. 7. Metronome suitable for guitar, piano, violin etc, to hp you have better rhythm. Specifications 1. Tone generator: C, C#, D, D#, E, F, F#, G, G#, A, A#, B 2. Battery: built-in 4.2V lithium battery 3. Charging port: USB adapter 4. Item size: 4.5 x 4 x 0.8cm / 1.8 x 1.6 x 0.3in 5. Item weight: 20g / 0.7oz 6. Package List: 1x Metronome 1x USB cable 1x Sling 1x Clip 1x User Manual(English & Chinese)