Tap function: enable you test your perfect tempo or tempo of track, tempo range from 30 to 280 bpm. Convenient to operate: easily fixed on a suitable place by the back side clip, the battery placing zone is easy to remove with a little effort, the front side designed with 5 buttons, press on the on/off and turn the device on, the select and up/down button is adopted to cycle through the functions. Accuracy: +/- 1/1000 (one thousandth); Beat value: 0, 1, 2, 3, 4, 5 ,6, 7, 8, 9; Volume adjustment: maximum volume, medium volume, minimum volume, mute. Power supply: 3V cell battery x 1 piece (package included), battery model: CR2032 Universal earphone jack: stereo earphone jack is available (3.5 mm), besides, you can easily change between TAP function and Metronome mode, an specific instruction is included. Mini professional metronome. LCD screen to display working information. Features clip and landyard hole design, easy to carry and fix. With LED indicator. Includes metronome mode and TAP mode. Supports stereo earphones. Suitable for guitar, piano, violin etc. Colour: black Material: Plastic Size: 5.5x3.2x1.29cm Package Contents: 1 * Metronome 1 * Battery 1 * Chinese and English instructions Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.