Amazon.com: Garmin Unisex - Adult Heart Rate Chest Strap Extender - 12.8" Extender Strap, Fits Pro, Dual, Run, Swim, HRM-Tri.Total up to 56" Chest Strap Length, Black, M : Electronics
Differences Between the 1st and 2nd Generation HRM-Run Straps | Garmin Customer Support
Garmin Hrm Pro Tri Heart Rate Strap Run 4.0 Swimming Running Hrm-dual Ant+ Bluetooth Bike Bicycle Cycling Computer Gps Hrm4-run - Bicycle Computer - AliExpress