The black and silver versions of the smart ring are on sale for $297, while the brushed silver and dark gray colors are on sale for $339, and the gold version is on sale for $424.

The Oura Ring 4 is our choice as the best smart ring, and its Brushed Silver variant is on sale for the first time during Amazon's Prime Day at 15% off.

In honor of Prime Day, Amazon is going against the norm with the first-ever price cut on Oura Ring 4: With a 15% reduction on all sizes, you can now buy the Oura Ring 4 in silver, size 10, for $297 from $349. Other sizes are also on sale, but some of them are already sold out.