Glow in Dark dial-After absorbing light for a day, the glow-in-the-dark feature stays active for 4 hours. The dial remains clearly visible for the first 1-2 hours, then gradually dims while maintaining enough illumination to help you locate the alarm clock in the dark - no fumbling required. Large Size- Size: 5.5" x 5.5" x 2.2",runs on 1 "AA" Battery (not included). Alarm clock stands up at an angle, high quality plastic, square face with white dial, black Arabic numerals, good decoration for tabletop, desk & shelf, bedrooms. Also large size screen and clear bold digits to display time, perfect alarm clock for elderly.