The optimized heart rate monitor from the Garmin HRM-Swim range of optional sensors is Garmin's very first heart rate monitor designed for use (pulse detection and recording) during swimming. Compatible with Forerunner 920XT/ 735XT/ 935 series devices, phoenix 3/5/5S/5X (PLUS), quatix 3/5, tactix. The manufacturer has redesigned it so that it can be used reliably even while swimming, which is impossible with a conventional heart rate monitor.
The design and materials used for the expansion part (chest belt) feature a special anti-slip surface, guaranteeing maximum adherence to the skin, even while swimming. Thanks to the new heart rate monitor, you can unify pulse measurement and recording not only during running and cycling, but also during swimming (in indoor pools or open water). During swimming, it "stores" pulse measurements in the built-in memory (20 hours of recording), where they are ready for instant synchronization with a compatible watch as soon as you surface or after your workout is over.