Clocks tend to come in 2 different movement types; quartz or radio controlled.
Quartz clocks use an electronic oscillator that uses a quartz crystal to keep the time regulated. These mechanisms are relatively inexpensive and compact. This makes quartz clocks the most commonly used timekeepers.
Radio controlled clocks are synchronised automatically to an atomic clock. There is a time code transmitted over radio waves from the atomic clock to the radio controlled clock. This means the time can be kept more accurately. Even to a few tenths of a millisecond. This makes radio controlled clocks a better option. This is also reflected in the price. To read more see Wikipedia.
Take a look through our range of clocks for your workplace and see which of our options suits you best.