Smart rings are making headlines across the world, and if you want to get on the hype train then the leading model is discounted for the first time in the US. The Oura Ring Gen 3 is now available from as low as $282 on Amazon, down from its usual price of $349. This is on the black colourway in the Horizon (circular) shape, though other shades such as silver, gold and brushed titanium also have savings of up to 19% off. This deal won’t last for long, as it’s part of the Amazon Prime Day sale, which ends tonight at 11:59pm. You’ll need to be a Prime member to take advantage of the discount, tho…