Straight from the Casio Vintage Collection comes a timepiece that never goes out of style. The B640 combines style with features Casio is known for such as an EL backlight and a 1/100th second stopwatch. This timepiece is the perfect complement to any outfit.. Features:1/100-second stopwatch50-meter water resistancePopular retro designLED BacklightBlack ion plated band Specifications:Case / bezel material: ResinStainless Steel BandAdjustable ClaspResin GlassBlack ion plated bandBlack IP50-meter water resistanceLED Backlight AfterglowFlash alert Flashes with buzzer that sounds for alarms, hourly time signal1/100-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 timesCountdown timerMeasuring unit: 1 second Countdown range: 24 hours Countdown start time setting range: 1 second to 24 hours (1-second increments, 1-minute increments and 1-hour increments) Other: Auto-repeatMulti-function alarmHourly time signalFull auto-calendar (to year 2039)12/24-hour formatRegular timekeeping: Hour, minute, second, pm, month, date, dayAccuracy: ±30 seconds per monthApprox. battery life: 3 years on CR2016 Size of case / Total weight: Size of case: 38.9×35×9.4mm Total weight: 49g