Garmin HRM-Tri Heart Rate Strap. Your heart rate is one of the most important indicators of your performing fitness. The HRM-Tri Heart Rate Strap is therefore the essential bit of training kit for anyone training to do a triathlon. The strap will accurately monitor your heart rate whether you’re swimming, cycling or running. The strap has been built to be super comfortable and to work with you as your train – never inconveniencing your movement Features. Specifically designed for triathletesComfortable, easily adjustable strapStores and forwards heart rate data to Forerunner 920XTBuy Garmin Heart Rate Monitors from Chain Reaction Cycles, the World’s Largest Online Bike Store.