tesrgre Power mode: USB, battery Control Mode: Mechanical display mode: digital How it works: Bluetooth Colour:black white Material:plastic Size: 12 x 12 x 24cm Package Contents: 1 x Smart sleep instrument 1 x English manual Only the above package content, other products are not included. Note: Light reflection 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.3. People who need to adjust their sleep have poor memory, poor skin, poor immunity, etc. If they do not sleep well at night, they will be in poor condition throughout the day, dizzy, and unable to concentrate. There must be various problems . 2. The sound of nature soothes the soul and deep sleep. The long-lost white noise is used as a delicacy to nourish drowsiness. With the process of urbanization, people are gradually "escaping" from nature. In a world full of buildings, the sound of nature will be particularly valuable. 1. brews the taste of sleep. Comfortable light brings tranquility to sleep from the visual senses. Fireflies are the in the summer night. On the of quiet lakes and gurgling streams, this quiet and cool taste is what sleep craves for. smell.