The SHARP Digital Alarm Clock with Dual Alarm offers dual alarms giving you the option to set two separate alarm times. For example, you could set one alarm for weekday wake times and the other for weekends The clock also has ascending alarm volume which gradually increases its volume, offering a gentler wakeup experience. This clock is electric operated; the battery backup does not power the clock. The battery backup is used for storing the time and alarm settings if the power is interrupted. During battery backup the clock' s display will not be lit. Once the power is restored the display will re-light. Check the time to make sure it is accurate and adjust if necessary. Product Dimensions: 5. 5 x 2. 3 x 2. 1