The HRM-Swim Heart Rate Chest Strap is specifically designed for swimmers. With a non-slip strap, this heart rate monitor transmits heart rate data to your compatible Garmin smartwatch devices and apps. The HRM-Swim is suitable for pool swims, open water swims, triathlon competitions, runs or bike rides as part of a multi-sport activity that includes a pool swim. Battery life: 18 months (swimming 3 hours per week).