Electro-luminescent backlightAuto light switch, selectable illumination duration (3 seconds or 5 seconds), afterglow Flash alertFlashes with buzzer that sounds for alarms, hourly time signal, countdown timer time up alarm, countdown timer progress beeper, and stopwatch auto start Low temperature resistant (-20°C) World time29 time zones (48 cities), daylight saving on/off 1/100-second dual stopwatches (ST1, ST2)Measuring capacity: 999:5959.99-InchMeasuring modes: Elapsed time, split time, 1st-2nd place timesOther: Auto start (ST1 only) Countdown timerMeasuring unit: 1 secondCountdown range: 24 hoursCountdown start time setting range: 1 minute to 24 hours (1-minute increments and 1-hour increments)Others: Auto-repeat, progress beeper 5 multi-function alarms (with 1 snooze alarm) Hourly time signal Full auto-calendar (to year 2099) 12/24-hour format Button operation tone on/off Regular timekeeping: Hour, minute, second, pm, month, date, day Accuracy: ±15 seconds per month Approx. battery life: 3 years on CR2025 Size of case : 46.7 × 43.2 × 12.7 mm Total weight : 59g