Marathon CL030025 Commercial Grade Jumbo Atomic Wall Clock with 6 Time Zones, Indoor Temperature & Date JUMBO DISPLAY - LCD display features 4.5-inch digits for easy viewing SELF-SETTING/ADJUSTING - Using radio frequencies broadcast from NIST's Colorado Atomic Clock. Automatic Atomic Signal- It cannot be turned on/off manually. MULTIPLE DISPLAY MODES - 12 or 24 Hour Display Formats with Indoor Temperature Display in Celsius or Fahrenheit 6 TIME ZONES - Choose between AST, CST, EST, MST, NST & PST with an option to turn off Daylight Savings Time BATTERIES INCLUDED - 3 C long life batteries included. This clock is designed with low battery indicator as well.This clock is designed with a low battery indicator as well.