Description: Bone conduction music box is easy to use, just put it under the pillow and open it to enjoy. You did not need to wear it into the ear, so long-term use will not feel uncomfortable. With MP3 function, it can be inserted into the SD-card. You can download your favorite music and stories to play, soothing your emotions and promoting sleep. It is made of good quality ABS material, durable to use. With built-in 300mAh battery, it has10 hours of music playback under full power, 300 hours of standby battery life, which accompanies you all night to sleep peacefully. The length of this product is 18.5cm, the width is 10.5cm and the height is 3cm. It is suitable for bedroom, dorm, home, etc. Item Name: Bluetooth-compatible Speaker Material: ABS Color: Blue, Black Interface Type: USB Frequency Response Range: 60Hz-15KHz Output Power: 3.7V Signal to Noise Ratio: 70db Power Supply Mode: Built-in Battery Battery Capacity: 300mAh (Included) Channel: 2.1 Play Time: 10 Hours Bluetooth-compatible Version: 5.0+EDR Number of Speakers: 2 Effective Distance: 10 Meters Support Format: SD-Card Features: Bone Conduction, Wireless, Long Endurance Size Details: 15cm x 4cm x 1cm/5.91" x 1.57" x 0.39" (Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Bluetooth-compatible Speaker 1 x USB Cable 1 x User Manual