It was named the 1440 because every day has 1,440 minutes in it. The Timex WR 50M uses a snap back for the cover plate for the battery. To change the battery you need a precision screwdriver set ...

The Timex Marathon is a battery-powered digital watch with a light that illuminates its face. Besides displaying the time, the Marathon has a timer, stopwatch, alarm and pulse mode to calculate heart ...