Oura made the Oura Ring 4 official this week, with better battery life, new designs, and improved accuracy . But for once, you don't need the latest model to get all the new features — as these are rolling out to all Oura wearers. So, if you're looking to pick up one of the best smart rings , now is a great time to buy the Oura Ring Gen 3 which is currently up to 22% off at Amazon with this early Prime Day deal.

But don't hang about — Oura has discontinued this model, so once retailers like Amazon are sold out, it won't be coming back in stock. It's also your last chance to invest in the flat-topped Heritage edition, as the Oura Ring 4 only is only available in the new fully circular, all-titanium design. The discount varies between Horizon and Heritage, and by color, but you could save up to $100 depending on your preferred configuration.

Alongside the new ring, Oura announced a redesigned companion app for Android and iPhone, making it easier to spot short and long-term trends, with three new features; Automatic Activity Detection, Fertility Insights and Daytime Stress. These aren't limited to owners of the latest Ring 4, as anyone with a Gen 3 ring will also be able to use them, so long as you take out Oura's subscription for $5.99 per month.

The main difference is that the data informing Oura's analysis should be more accurate on the Ring 4. That doesn't mean that the Oura Ring Gen 3 isn't worth the money though. The company goes to great lengths to test the accuracy .