Garmin Forerunner 735XT review: A slim, lightweight triathlon watch that's worth the money - CNET
The 8 Best Triathlon Watches
Amazon.com : Polar Verity Sense - Optical Heart Rate Monitor Armband for Sport - ANT+ and Dual Bluetooth HRM - Waterproof HR Sensor with only One Button - Compatible with Peloton, Zwift
How to pair Heart Rate Monitor to a Garmin watch - YouTube