Bluetooth e Ant + Monitor di Frequenza Cardiaca Cinghia Della Cassa Della Cinghia per Strava Wahoo Runtastic Endomondo Amazfit Stratos Cardio Cintura Cardiofrequenzimetro - AliExpress
Amazfit GT 4 range gets the ability to connect to external heart rate monitors
How to connect Amazfit watches to external heart rate chest straps - YouTube