Garmin Fenix 3 - Garmin: Replacing the Battery in your Heart Rate Monitor ( HRM) The CR2032 batteries in your HRM-Run, HRM-Swim or HRM-Tri straps will last approximately 18 months, depending on use.
Garmin Swim/Tri HRM | Luke's Electronics
The 7 Best Heart Rate Monitors for Your Peloton Bike
Garmin Hrm Tri Battery Type on Sale, UP TO 55% OFF | www.quincenamusical.eus
Forerunner 920XT - Replacing the HRM-Swim Battery and the HRM-Tri Battery
Battery Replacement Instructions for Premium Feature HRM Straps | Garmin Customer Support