Garmin’s HRM-Swim is designed to be used during open water and pool workouts. It has a unique non-slip design so you can just swim and not constantly adjust the strap, which in turn provides you with more accurate training data. When it is paired with the Forerunner 920XT data is automatically transmitted to your Forerunner when it is out of water. Battery life for the HRM-Swim is up to 18 months. Of course the HRM-Swim uses ANT+ wireless technology so pairing with either a Forerunner 920+, Enduro, fenix 3, fenix 5, fenix 6, fenix 6 Pro Solar, or epix is easily done.