AX725 AX Pro Memory Series Stopwatches are professional timing devices with significantly increased functionality going beyond our tremendously successful Classic X (WOS) Series. The AX725 has Exclusive "AOS" 4.5 Operating System with Twin Left-Right button operation feature, 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" Extra Performance Case.