product specification LED Light with Afterglow Dual Time Muli-functionalarm with snooze 1/100 second digital stopwatch Measuring capacity: 23:59'59.99" Measuring modes: Elapsed time, split time, 1st-2nd place times Hourly time signal Auto Calendar (pre-programmed until the year 2099) Accuracy: +/-30 seconds per month Battery CR2025 Approx. battery life: 10 years 10 year battery Water Resistant