PSA: Look at the heart rate sensor of your fenix 5. Has it cracks like mine? If yes, it's a common problem. Send it to Garmin and get a free replacement. Do
Amazon.com: Garmin fēnix 5X Plus, Ultimate Multisport GPS Smartwatch, Features Color Topo Maps and Pulse Ox, Heart Rate Monitoring, Music and Pay, Black with Black Band (Renewed) : Electronics
Garmin fēnix® 5S Plus | Multisport GPS Watch
Garmin fēnix® 5S Plus | Multisport GPS Watch
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Garmin fēnix® 5 Plus | Multisport GPS Watch
Garmin Fenix 5/5S/5X Plus In-Depth Review (with Maps, Music, Payments) | DC Rainmaker