Bluetooth 5.0 ANT+ Heart Rate Monitor Armband with HR Zones/Calories Burned Optical HRM Sensor for Fitness Cycling Running - AliExpress
Amazon.com: Scosche Rhythm 24 Fitness Armband: Hyper Accurate Tracking with Dual Band ANT+ and BLE Bluetooth, Heart Rate Monitor, Waterproof & Dustproof, Built-in Memory for Garmin, Peloton, Wahoo, Strava & More :