The Polar S625X is like having a performance lab with you on every workout. With multiple functions and tools, this heart rate monitor helps you achieve the maximum workout every time.Exercise:Wireless ECG accurate heart rateExercise Set-5 extended exercise profilesOwnCode, OwnCal, OwnOptimizerFitness testAuto/Manual target zone (of max or bpm) with visual, audible alarm-3HR max (fitness test-based)Interval timersIndependent CountDown/Up timerAvg and max heart rate of each lap and total exerciseHeart rate displayed as bpm and percentage of maxRelaxation rate during exerciseRecovery measurement (HR/time)Online recording with opt. IR InterfaceAuto lap recordingExercise dateAltitude and ascentRunning speed displayed in pace or kmph/mphDistance-based interval trainerComputer connection:2-way IR data communicationUpLink, settings upload from Polar website or SW to wrist unitPrecision Perf. analysis SWOpt.IR Interface (RS 232 serial port or USB port)Recording function:99 exercise files (with summary)Training file info page with date, timeTime of total exercise in target zoneTarget zone limitsAvg, Max heart rate of total exerciseLast OwnIndexWatch:Time of day(12/24h) with alarmDual time zoneDate, weekday indicatorStopwatchAuto exercise reminder (visual)Manually-set reminders (visual/alarm)Water resistant 30 metersBacklightTransmitter belt:WearLink31 coded transmitterT61coded transmitter(compatible)