AX 605 AX Pro Series Stopwatch is great for Event Timing . Extremely large digits for easy viewing on the field, track, or by the pool add to the appeal of these stopwatches. Exclusive "AOS" Operating System with Twin Left-Right button operation feature its designed to give coaches, athletes, and timers the most precise timing available. All AX Pro Series Stopwatches are cased in ACCUSPLIT's distinctive, ergonomic designed "X" Case.