Sshhh… Shhh - Clinically tested technology that helps babies stop crying. Sounds that the baby recognizes from the womb. Six soothing melodies. Play calming melodies while falling asleep: Psst, heartbeat sound, white noise, ocean waves, lounge music, or lullabies. Automatic shut-off: The sound automatically turns off after about 20 minutes. Sound sensor: The sound is automatically activated when your baby starts to cry. Choose your own volume: Set the volume to your preferred level. Portable: Can be attached to a crib, car seat, or stroller.