I've tried chest straps once or twice and found them pretty uncomfortable, though its possible I would get used to it. The advantage of these standalone optica

I've tried chest straps once or twice and found them pretty uncomfortable, though its possible I would get used to it. The advantage of these standalone optical sensors is that because they are smaller & lighter, and sit on the fleshier upper arm, they are much more accurate than sensors on a watch, despite being the same tech. Edit: DC Rainmaker's analysis shows that these are more or less as good as a chest strap (https://www.dcrainmaker.com/2019/03/polar-oh1-plus-optical-hr-sensor-in-depth-review.html https://www.dcrainmaker.com/2019/03/polar-oh1-plus-optical-h...)