Oura announced the fifth generation of its new smart ring on Thursday, with plans to ship starting June 4. I don’t have a review unit in my hands yet, but according to press materials provided by Oura, the new ring will be the thinnest on the market, priced at $399 to $499 depending on color. At 6mm wide, the company boasts that this will be the thinnest smart ring, and I think they’re right. The thinnest ring I’ve reviewed is RingConn’s, and you can see a photo in this review of the Oura Ring 4 next to the RingConn 2. The current Oura Ring 4 is about 8mm, and the RingConn is about 7mm. (Yes, I keep a set of calipers on my desk, don’t you?) At 6mm, the Oura 5 will definitely be thinner. Smart rings have always been clunky compared to traditional jewelry rings, so this change will be nice to see.Oura Ring 5: Prices and sizingOura is charging $399 for black and silver, and $499 for all other colors, which now include a matte black and brushed silver. The gold and rose gold (now called Deep Rose) finishes are now a slightly different shade and have better scratch resistance. An Oura subscription still costs $5.99 per month or $69.99 per year.Sizing for the Oura Ring 5 is slightly different from the Oura Ring 4, and the company recommends getting a new sizing kit rather than going with your old size. While the Oura Ring 4 smoothed out the ring’s interior, the Oura Ring 5 is bringing back a smaller version of those sensor bumps to give better contact with the skin. The size range has contracted a bit: The available sizes now range from "6" to "13" (no longer "4" to "15"). The new sizing means that your old charger will no longer fit, so if you ponied up for a charging case for the Oura Ring 4, you’ll have to do so again for the 5. As with the 4, the 5’s charging case is a $99 add-on and does not come with the ring.Oura Ring 5: New software featuresAlong with the hardware, Oura is announcing new software features. You’ll be able to track detailed workout metrics from the app, which may soften my stance on not using smart rings for workout tracking. There’s a new Health Radar feature that’s meant to notify you when your biometrics seem out of whack, similar to the Symptom Radar that is supposed to pick up on whether you’re getting sick. (I’ve written before about some pretty big caveats to Symptom Radar, but that’s another story.) The new Health Radar will notify you if Oura thinks you are showing signs of high blood pressure or “breathing disturbances,” which is code for sleep apnea. Oura says the app won’t try to diagnose these conditions, but rather flag when you might want to see a professional to get checked out. Conveniently, Oura just partnered with Resmed, which offers sleep technology like CPAP devices. The Oura app will also offer some new features for GLP-1 users, including tools for monitoring weight, dosage, and side effects.