H9Z is our first rechargeable chest strap heart rate monitor. We made great effort on improving the using experience. 

If you are interested in why we want to make the HW9 and more details of HW9, please read this article.

How did I realize the importance of monitoring heart rate The correlation between heart rate and exercising How to calculate MHR Get to know 5 Heart rate zones How to monitor your heart rate Differences between chest heart rate monitors and armband ones Review on COOSPO  HW808S heart rate monitor What's HRV