Mens Digital Sports Watch Alarm Stopwatch 100M - Black Resin 100M Water Resistant LED Backlight (Super Illuminator) w/Afterglow Dual Time Daily Alarm, selectable flash alert/vibration alert Hourly Time Signal Vibration Alert (Daily Alarms, Countdown Timer, Hourly Time Signal) 1/100 second stopwatch Countdown timer Full Auto Calendar (pre-programmed until the year 2099) 12/24 Hour Formats Button operation tone on/off Accuracy: +/- 30 seconds per month Battery: CR2032 Approx. battery life: 10 years