This heart rate watch can be used as your exercise aids， motivational tools， trendy accessories， data analyses and personal trainer， aiding you on your journey towards your health and fitness targetWireless receiving heartbeat signal transmitted from heartbeat brooch， chest band frequency is AM5.3KHzTime display: Hour， Minute， SecondAlarm clock functionGive alarm when heart rate exceeds the upper and lower limit values (60-220)Timing (maximun time-keeping is 23 hours， 59minutes， 59seconds， 99)12/ 24 hour display formatEL backlightKeystroke toneDial size: Approx. 4.2cm x 1.5cm/ 1.65" x 0.59"Chest transmitter strap: about 63-92cm/ 24.80"-36.22"(Elastic)Package Include:1 x Heart Rate Monitor Sport Watch1 x Heartbeat Chest Band1 x Instruction Manual