Yogasleep Hushh Portable Sound MachineTime tested by the sound specialists at Marpac,& 3 sound options promote sleep and mask noise: bright white noise, deep white noise, or gentle surf. Simply fasten Hushh to a stroller or car seat using the included baby safe clip or place it on any surface. The simple interface is easy to use and operate with one hand. Offers the ability to lock Hushh at a desired setting and volume to prevent younger hands from altering the sound or turning the unit