The Marathon CL030059 Reverse LCD Display Jumbo Atomic Wall Clock is self-adjusting and self-setting, eliminating the need to manually input the time and date. Simply insert the batteries provided with the clock and it will synchronize to the time set out by the atomic clock in Colorado once the signal is received. The Reverse LCD Display Jumbo Atomic Wall Clock with 4.5-inch digits is extremely legible even at a distance. The atomic feature ensures that the time, day and date are always accurate. It even adjusts automatically for daylight savings (this option can be turned on or off). You can choose between 6 time zones (AST, CST, EST, MST, NST & PST), two more than many of our competitors. You can also choose to have the time displayed in 12 hour or 24-hour military time and ambient temperature in Celsius or Fahrenheit. The industrial but modern design of this clock makes it perfect for any office, boardroom, classroom, hospital or any large room. You can choose to use the cutout on the back of the clock to easily hang on a wall using a nail or screw (not included), or use the convenient fold out table stand.