Another thing worth noting is a lot of people complain about the rings getting scratched, and showing signs of wear pretty quickly. I wore both of these nonstop throughout the day (including while lifting weights) and noticed the silver Ultrahuman was more resilient than the gold Oura, which did get a bit scratched up.

According to the complaint filed in U.S. District Court for the Northern District of California, Bal was an early investor in Oura, as well as serving as the company’s “primary marketing arm” in its early years as a cash-strapped start-up.

With an improved design and more features, the Oura Ring 4 has made its way onto my hand for good, but I'm not giving up my fitness tracker just yet

Amazon Prime Day is here once again and the celebrity-loved Oura Ring 4 is on sale for the first time ever. Save up to 21% off through July 11.

Turn your ring stack into a smart one with the Oura Ring, now 15% off for Amazon Prime members. It tracks sleep, stress, activity, and more, and even includes your first month of membership free. Choose from several finishes. The 30-ounce Stanley Quencher is on sale at Amazon for Prime Day. You can get the color "Tigerlily Plum" for just $21.

A travel writer and frequent flier discovered how to avoid jet lag, thanks to her Oura Ring, which is on sale for Amazon Prime Day. Find out how the wellness gadget acts as the ultimate jet lag self-care hack and get one for yourself at Amazon,