Stereo Pillow Speakers - The Best Partner of Learning English Say Goodbye Hearing Loss Enjoy your favorite music playlists while lying or sleeping. Say goodbye to head phones oppression, say goodbye to the damage to the hearing. Import the bass sound unit,bass,treble clear and natural. USES: coat, noble and comfortable, durable. Open type design, compatible with various types of pillows. 3.5 mm international goods, general all kinds of play equipment. Scientific tracks, audio cavity design, only the master can hear sound. Speaker diameter: 40mm Impedance: 32 S.P.L: 114db S.P.L. at 1KHz Rated Power: 200 mW Aggregate Capacity: 50 mW Frequency Response: 20Hz-20,000 Hz