Bone conduction: This under pillow speaker can transfer the audio via the bone, so it won't easily disturb others while working. Auto power off: This bone conduction wireless speaker will turn off automatically after 30 minutes, so you don't need to turn it off manually while sleeping. Long work time: Built-in large capacity polymer battery, this wireless loudspeaker can provide 20 hours of music playing time and has 300 hours of standby time. Other function: This under pillow sound box supports a memory card, which allows you to play MP3 music directly from the memory card. Easy to connect: Support bluetooth-compatible 5.0, this under pillow subwoofer is easy to connect with most types of phone and tablets.