Check this out! The first of its kind; the Lifetone Bedside Fire Alarm and Clock uses a 520 Hz sound pattern proven by the Fire Protection Research Foundation to be more effective at alerting and awakening people with hearing loss, seniors, children, and heavy sleepers than standard fire alarms. The Lifetone HL is a state of the art fire alarm and an attractive and easy to use alarm clock. The Lifetone sensor listens for your existing smoke detectors and then sounds its low frequency, 520Hz square wave sound pattern. Features include: Extra-large clock display, alarm time display, month/date/day display, bed shaker and test button. Dimensions: Length 11in, Width 5in, Height 8.6in