Garmin Forerunner 25 HRM1 Noire/Violette Small - 010-01353-70 - Multisports Watches and Outdoor GPS - IceOptic
Garmin Hrm1g / Running Heart Rate Monitoring Chest Strap Ant + Waterproof Brand New Original First Generation Hrm Black No Box - Compasses - AliExpress
Support: Using a Garmin Heart Rate Monitor - YouTube