Atomic Time with Manual Setting Automatically Sets to Exact Time Accurate to the Second Automatically Updates for Daylight Saving Time (On/Off Option) 4 USA Time Zone Settings.Simple Operation: Insert 1 AA Alkaline Battery For precise time in the home or office, atomic analog clock from La Crosse Technology Frame features chrome-colored finish with black inner trim; flat lens covers clock face from dust and debris Clock resets regularly by radio-control to match the US Atomic Clock in Colorado and adjusts automatically for daylight savings time Users select from 4 time zone setting buttons on the reverse for area time; requires separate purchase of 1 AA battery Clock measures 10 inches in diameter and 1-2/3 inch in depth with a 7-1/4-inch diameter face; this clock is covered by a 1-year warranty