The Baby Shusher stops crying by engaging the natural calming reflex of your baby. It uses a parenting technique made popular by Dr. Harvey Karp in the "Happiest Baby on the Block" book. The Baby Shusher incorporates the fourth 'S' of the "Five S'" — shushing. With loud, rhythmic shushing noises, the Baby Shusher draws on ancient, time-tested practices. Plus, the Baby Shusher allows you to set your timing preference with either a 15-minute option or a 30-minute option and it has built-in volume control so that it's louder than baby's cries, which is proven to help calm babies.