The main differences between the HRM 200 and HRM 600 belts lie in functionality, battery, durability and data tracking.

The HRM 200 is an entry-level belt with a user-replaceable battery (CR2032 button cell) offering battery life of up to one year, ANT+ and Bluetooth connectivity, and basic heart rate tracking. It does not track running dynamics or record activity without a watch. It is available in two strap sizes (XS-S and M-XL).

The higher-end HRM 600 has a rechargeable battery with a battery life of around 2 months, is more water-resistant (5 ATM compared with 3 ATM for the HRM 200), and offers advanced functions such as tracking of running dynamics (cadence, stride length, ground contact time, etc.), activity tracking (heart rate, heart rate, etc.) and activity recording.), activity tracking (steps, distance, calories, minutes of intensity), and the ability to record sessions without a watch. It's designed for athletes looking for more advanced analysis, particularly runners and team athletes. It is available in sizes M-XL.

In summary, the HRM 200 is suitable for basic use and long battery life, while the HRM 600 targets demanding users with advanced sports tracking needs and a rechargeable battery.