The Fastime 23 stopwatch times up 9 hr 59m 59sec with an accuracy to 100/th second. It features a rugged water and shock resistant case and a rear hatch for ease of changing the battery.With START, STOP, RESUME (TIME OUT) or RESET, and the option to take CUMULATIVE OR LAP SPLIT TIMESCumulative or lap split times can be changed during the timing of an event. This means that if you start timing a lap in cumulative mode, you can take split times within a lap. If you switch to lap split mode during the last segment of the lap, you will capture the lap time and the stopwatch starts again from zero unless you press stop.ONE / TWO FAST FINISH: Press the split button to take the time of competitor 1. Press the stop button then the split button to show the time of competitor 2.Ideal for circuit racing of any kind including Karting and Bike racingThe Fastime 23 requires a CR2032 lithium battery (included)1 Year manufacturers warranty.