Bluetooth 5.4 mode:Adopting Bluetooth chip, equipped with high performance chip, faster and more stable, low latency and low power consumption, clearer sound. 10 kinds of stress-reducing sleep-aiding sounds:Let you say goodbye to negative emotions, different sound scenarios to make you feel calm and sleep soundly. Don't disturb the person next to your pillow:Vibration playback exclusive music, watching short videos, listening to music, not disturb the pillow. Light weight:Slim and design, flat shape, easy to put in your pocket, convenient to carry. Multiple playback modes:Support Bluetooth playback, comes with TF card slot, supports up to 128GB TF card playback. Timer shutdown:Automatic timer shutdown after 60min, easy to set, no need to get up to operate, sleep until dawn. Powerful 8h battery life:300mah rechargeable lithium polymer battery, fast charging, long battery life. Product name: Bluetooth bone conduction music box (TF models) Charging voltage: 5V/300mA Operating voltage: 3.7/4.2V Battery capacity: 300mAh Bluetooth version: 5.4 Bluetooth distance: 10m Charging interface: Type-C Charging time: 2 hours Playback time: 8 hours Colour:Gray Material:plastic Package Contents: 1 x bone conduction sleep monitor 1 x USB cable 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.