Review on COOSPO Bluetooth & ANT+ Heart Rate Monitor Armband - Optical HRM Sensor, Waterproof IP67, Fitness Tracker Armband Compatible with Zwift, Wahoo Fitness, Endomondo, Peloton - Includes One Extra Free Armband by Scoony Taker

I really like this monitor. I used to have a chest monitor, but it was uncomfortable during workouts and started causing rashes. This monitor is great as it can be worn on the forearm or bicep and doesn't interfere with poses during workouts. I use it with DDPYoga and it works great with the app. Just remember to turn on your location and bluetooth before enabling the ddpynow app. I checked my beats per minute with a chest monitor and a blood pressure monitor and it's definitely plus/minus 1-3 beats per minute.