high quality 10 Soothing Sounds Create a Sleeping Atmosphere---white noise machine offers 10 soothing sounds, including white noise, crickets, sea wave, clock, birds, heartbeat, streams sound, and 3 different lullabies. Intelligent Sound Detection Plays Music Automatically---In sound detecting mode, the music will auto turn on If continuously receiving the sound exceeds 10 seconds within max.10 meters, and then auto stop playing after 15 minutes, keep cycling until no power. Excellent Rechargeable Battery Offers Long Play---The noise machine equipped with a built-in 300mAh rechargeable battery, 1 hour short charging can continuously play for up to 23 hours. 3-Level Timer And Adjustable Volume Helps Handle the Matter Timely---Users can set the timer for taking naps, temporary relaxation, meditation, concentration while studying and working.Long press next song or previous song button you can customize the sound, volume (from very low to adequately high), non-stop playing or using timer on it.