I had a Vivofit 2 with a Heart monitor chest strap which was very accurate. I wanted the Vivosmart4 because it provides average heart beats after a workout session. The problem is the Wrist heart detection sensor is off by 10 -15 beats when heart beat goes up. It’s resting heart beat is very close to accurate.
https://www.amazon.com/Garmin-Vivosmart-Activity-Fitness-Midnight/dp/B07S1KXTZZ

