Application: This under pillow speaker can accompany you to sleep, and it will turn off after 30 minutes, so you can focus on your sleep.Safe to use: Built-in polymer battery, this wireless loudspeaker is rechargeable and features a dual MOS battery protection circuit.Comfortable to use: With a small and thin bar appearance, this under pillow speaker wont make you feel uncomfortable while sleeping.Advance technology: Adopts bone conduction technology, this wireless stereo speaker will provide a clear sound to you, and it wont easily disturb other people.Easy to use: With a bluetooth-compatible 5.0 function, you can connect this under pillow speaker to a phone and start to play your soothing music to help you sleep.Specification:Bluetooth-compatible version: 5.0.Connection range: Approx. 10m/32.81ft.Material: Plastic.Working voltage: 3.7-4.2V.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 300 hours.Charging voltage: 5V, 400mA.Charging time: About 2 hours.Size(LxWxH): Approx. 15.5x3.6x1.2cm/6.10x1.41x0.47 inch.Channel: 2.Audio crossover: Full-range.Input power: 25W.Rated power: 4W.Impedance: 2.Sensitivity: 32dB.Total Harmonic Distortion: 1%.Note:There might be a bit of color distortions due to different computer resolutions.There might be a slight error due to different hand measurements.Package Includes:1 Piece Speaker(with 1 Piece Charging Cable, 1 Piece User Manual).