sms wrote:
https://www.crevenbike.com/

One of these showed up in my P.O. Box. At the 2018 Interbike in Reno I
stopped at this booth. It was the last day and the booth person insist
that I take the demo model of a different seat post.

I guess I'd better try it to see how my heart rate changes.


Well, colour me skeptical, but tell us how it works.