SELF-SETTING, SELF-ADJUSTING CLOCK - Simply insert the batteries provided & the Marathon Atomic Wall Clock will synchronize to the correct time using radio frequencies broadcast from NIST’s ...

The requirement to run a qualifying marathon was introduced in 1975, with the time set at 04:30. But in 2000, the time was adjusted to 05:00 when the finish time was extended from 11 to 12 hours ...