stodoc white noise bluetooth 5.0 speaker sound machine & wireless fast charger for sleeping baby adult, sleep therapy for home, office & travel, 7 relaxing & smoothing nature sounds, auto-off timer stodoc we pick up 7 wonderful nature sounds out of 35 sound tracks, based on the survey results of 500+ people who suffered insomnia as well, then get these 7 relaxing & smoothing sounds transformed into non-looping soundtracks, embed into our zs1001, and ready to help the next poor soul who lost his or her good sleep