24 hours Countdown start time setting range: 1 second to 24 hours (1-second increments, 1-minute increments and 1-hour increments) 5 daily or one-time alarms 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 CR2016 Size of case: 55.1 X 52.5 X 16.3 mm total weight: 69 g LED:White