1. alarm switch: top left, push up to "alarm" to make 125db alarm sound, and push down to "off" to turn off. 2. Time switch: bottom left, Press the "time" button to display the time, 10 seconds to automatically turn off 3. switch setting: bottom right, press "set", then press "time" to adjust time, and then press "set", you can adjust in turn with "time" button, 24/12 hours. 4. charging: the four blue lights under the screen account for 25% of the electricity each, and when the electricity is insufficient, the head charges the product. There is enough electricity to work for a week. The rechargeable belt time displays the alarm clock, and four blue lights can indicate whether the electricity is enough. Size: 260 * 40 * 12mm Weight: 42.2g Decibels: 125DB Material: ABS + silicone Battery capacity: 130mAh