Shock resistant. Electro-luminescent backlight - Afterglow. Flash alert - Flashes with buzzer that sounds for alarms, countdown timer time up alarm. Dual time. 1/100-second stopwatch. Countdown timer. Daily alarm. Current time display style (5 styles and secret style). Full auto-calendar (to year 2099). Time Format: 4 (selectable) - 12 - 11: 12-hour format that does not distinguish between noon and midnight, which are both displayed as 12:00; 0 - 11: 12-hour format that does not distinguish between noon and midnight, which are both displayed as 0:00; 0 - 23: 24-hour format that distinguishes between noon (12:00) and midnight (0:00); 6 - 29: 24-hour format using a day that starts at 6:00 a.m. and ends at 5:59 a.m. Button operation tone on/off. Regular timekeeping: Hour, minute, second, pm, month, date, day, daylight saving on/off. Accuracy: 30 seconds per month. Case diameter: 41.1 X 39.0 X 11.1 mm.