Lifetone Safety is dedicated to protecting a number of individuals who may be at risk of not waking to their fire alarms. These groups include: Children:Compared to adults, children spend much more of their total sleep cycle in "deep sleep." During deep sleep the brain turns its sensitivity to external sensory input way down, sort of like locking itself in its own dark, sound-proof room. Only very special auditory stimulation—like the low-frequency "square wave" pattern of the Lifetone HL—can break through and interrupt the brain's self-isolation during deep sleep. Seniors: More and more older adults are enjoying independent living, but there are also greater risks. For seniors 75 years old or older, the risk of fire death skyrockets to three and a half times the national average. People With Hearing Loss: Hearing loss is a much more pervasive problem than most people realize. Including the hearing impaired who have moderate to severe hearing loss, an estimated 70 million Americans—nearly a quarter of the population—are hard of hearing to some degree.