Silicone Sports Watch Band For Garmin Fenix 6/6X Pro/5X/5X Plus/Fenix 3/3 HR | eBay
Amazon.com: SABAKE Watch Band for Garmin Fenix 6X/6X Pro, Quick Fit 26mm Wristbands,Compatible with Fenix 6X/6X Pro Fenix 5X/5X Plus Fenix 3/3 HR : Electronics
Garmin fenix 6 series optical heart-rate-sensor test - YouTube