1. Unique earphone interface, can be connected with MP3, MP4, CD, radio and other audio sources. 2.8 kinds of natural sounds. 3. Superior-quality fabric outside and foam stuffing inside, ensuring comfortable massage. 4. Smart and portable, can be used any where any time. 5. Ergonomic design naturally conforming to contour of your neck. 6.4 AA batteries(not included) operated.