Round wall clock is automatically set by the atomic clock and automatically adjusts to Daylight Saving Time. The atomic clock is accurate to one second per million years and designed to work in the continental United States. Face features easy-to-read, black Arabic numbers on a white face, black hour hand, black minute hand, red second hand and glass cover. Wall clock runs on one AA battery (sold separately).Round wall clock is automatically set by the atomic clock and automatically adjusts to Daylight Saving Time. The atomic clock is accurate to one second per million years and designed to work in the continental United States. Face features easy-to-read, black Arabic numbers on a white face, black hour hand, black minute hand, red second hand and glass cover. Wall clock runs on one AA battery (sold separately).