The product has a percussion rhythm speed function: TAP function, can accurately test your own heart beat speed or a song beat speed, has two-channel headphone output. Features: The back of the product has a clip and lanyard hole results designed to facilitate the fixed. Import sound unit, sound is loud and the sound is nice. Adjustable control. Stereo earphone jack is available. Tap function enables you to test your ideal tempo or tempo of a track. Multi-functional and professional metronome is lightweight and portable, easy to use. Specifications: Color: yellow, blue, red, white, black (optional) Speed : 30-280bpm changes: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 Accuracy: plus or minus 0.001 (thousandth) adjustment: maximum , medium , minimum , mute Battery: 1 * CR2032, 3V, 240mAh (not included) Item size: 130 * 56 * 32mm / 5.1 * 2.2 * 1.3in Item weight: 23g / 0.8ounce Package size:130 * 80 * 40mm / 5.1 * 3.1 * 1.6in Package weight: 33g / 1.2ounce Package list: 1 * Metronome 1 * User Manual