Description: Application: This beneath pillow speaker can accompany you to sleep, and it will flip off after 30 minutes, so you can focus on your sleep Safe to use: Built-in polymer battery, this wireless loudspeaker is rechargeable and lines a twin MOS battery defense circuit Comfortable to use: With a small and thin bar appearance, this beneath pillow speaker won&;t make you feel uncomfortable while sleeping Advance technology: Adopts bone conduction technology, this wi-fi stereo speaker will present a clear sound to you, and it won&;t easily disturb other people Easy to use: With a bluetooth-compatible five function, you may join this under pillow speaker to a telephone and start to play your soothing song to help you sleep Specification: Bluetooth-compatible version: five Connection range: Approx 10m/32 Material: Plastic Working voltage: 3 Vocalism unit: Bone conduction Frequency response range: 40Hz-20KHz S/R rate: ≥75dB Battery: Polymer battery, 400mAh(Built-in) Music play time: About 20 hours Standby time: About three hundred hours Charging voltage: 5V, 400mA Charging time: About 2 hours Size(LxWxH): Approx 15/6 inch Channel: 2 Audio crossover: Full-range Input power: 25W Rated power: 4W Impedance: 2Ω Sensitivity: 32dB Total Harmonic Distortion: 1% Note: There is probably a bit color distortions due to various computer resolutions There is probably a slight error thanks to diversified hand measurements Package Includes: 1 Piece Speaker(with 1 Piece Charging Cable, 1 Piece User Manual)