✅±1BPM OPTICAL HEART RATE ARMBAND & CALORIE TRACKER: COOSPO HW9 heart rate armband uses optical heart rate technology to provide accurate heart rate and calorie burn data, achieve a monitoring error of ±1BPM.

✅HEART RATE ZONE MONITORING& HRV FUNCTION: HW9 has a 5-color LED indicator light for Heart Rate Zone Training，that show your heart rate zone at a glance, so you can optimize your intensity levels at the right time. Also support heart rate variability (HRV) function.

✅COMFORT TO WEAR: Armband heart rate monitor is a great alternative to heart rate chest straps and wrist-based devices. Armband HRM sensor allows maximum freedom of movement and works in countless different sports.HW9 with soft ,breathable and adjustable band for all training and exercise.

✅CONNECTIVITY: Bluetooth 5.0 and ANT+ guarantee that you can connect COOSPO HW9 Armband heart rate sensor with GPS bike computers/APP/Fitness Devices/Running Watches. You can have two simultaneous Bluetooth connections with the latest technology.

✅SUPPORT MAX HEART RATE CUSTOMIZATION: Heartool/Coosporide App allow you to customized your real max heart rate value with HW9,sothat reach your true heart rate zone ,you can optimize your intensity levels at the right time. (Default MAX heart rate was 200bpm)

✅MAX HEART RATE VIBRATION: when your heart rate higher than MAX heart rate value or your customized value,HW9 armband with a vibration warning, guarding your training safety.

✅RECHARGEABLE BATTERY: Provides up to 35 hours of battery with fast-charge and a magnetic charger.To extend battery life, please use a DC 5V power adapter or computer USB port for charging.

✅RECOMMENDED APP: COOSPO Bluetooth 5.0 heart rate armband is compatible with 200+ APP like Wahoo Fitness/Strava/Polar Beat/DDP Yoga/HR monitor/CooSporide/Elite HRV/Zwift.