The Invisible Clock is an assistive device that works great for timed voiding programs, medication reminders, meeting timer, exercising and literally hundreds of uses where a flexible timer is needed. The unit has 12 daily alarms that can be set for specific times. This provides you with flexibility in alerting you or your child to perform a specific task when a specific interval is not practical. Or, you may choose a specific interval where it is more convenient. In fact, you can choose both. The 12 Alarms are Automatically Organized by the time of day, so it's easy to keep track of your programmed alarms and easy to check, erase, or set additional alarms. The Invisible Clock uses a vibration system (similar to that of the common pager) that is private yet easy to feel. If you choose, you may adjust the vibration or beep to low for a gentle and quiet reminder, or to medium or high for a stronger alert. The single AAA battery is easy and inexpensive to change. Affordably priced, easy to program and use.