In F3K competitions, timers are short of time to start, stop, restart and write flight times between launches. Most of them use two stopwatches, so they get short of hands. F3K has the following features: Start and stop of main chronometer with on-screen button or volume button Automatic zero reset Keeps track of previous times Secondary Working time stopwatch (10, 7 or 15 min selectable by longpressing st chronometer) If not yet running, Working Time stopwatch starts when main chronometer is fi