Shock Resistant. 100M Water Resistant LED Light with Afterglow, Multi-function Alarm Countdown Timer, Measuring unit: 1 secondCountdown range: 24 hours, Countdown start time setting range: 1 second to 24 hours (1-second increments and 1-hour increments), Other: Auto-repeat function, 1/100 second stopwatch, Measuring capacity: 00'00"00-59'59"99 (for the first 60 minutes), 1:00'00-23:59'59 (after 60 minutes), Measuring unit: 1/100 second (for the first 60 minutes), 1 second (after 60 minutes)Measuring modes: Elapsed time, split time, 1st-2nd place times, Hourly Time Signal, Auto Calendar (pre-programmed until the year 2039) 12/24 Hour Formats, Accuracy: +/-30 seconds per month, Battery CR1616, Approx. battery life: 2 years, Module 2902, Size of case/total weight, 34.5 x 35.4 x 13.1mm / 36g.