This atomic analog wall clock displays highly visible 1 1/2 in. time numbers that are easily seen across the room. It is radio-controlled so time sets automatically and is always correct even with DST (Daylight Saving Time). The clock movement has a very specialized AM radio receiver that is tuned to receive a 60KHz WWVB time signal broadcast from the U.S. Government's atomic clock in Boulder, Colorado, and Fort Collins. The signal is an AM radio signal - adjusts itself to the U.S. atomic clock's time signal depending on its location. 11 1/2 in. diameter across. Silver trim. White face with black numbers. Uses 1 ''AA'' battery (not included). 1 inch deep.