I've only had the Oura Ring 5 on my finger for 48 hours, but I can already tell this ring is going to be a trendsetter. 

I posted a short unboxing video on my social media showing it next to with my current Oura Ring 4 and was flooded with questions about referral links, sizing kits and color options. 

As a wearables reviewer, my feed is plastered with gadgets, and I'm used to the occasional "I want one" comment. But I've rarely seen the kind of immediate buying interest that the Oura Ring 5 generated, predominantly from women asking for referral links, sizing advice and color recommendations.

The minute I took it out of the box and slipped it on my ring finger next to my Oura Ring 4, I was sold, too. There's still a lot left to test beyond the aesthetic, but this ring proves we're all just craving wearable tech that doesn't look like tech at all.

When the original Oura Ring debuted in 2015, it was a chunky band with the heft of rings awarded to World Series winners that pretty much swallowed the entire base of your finger. It's since slimmed down considerably, so much so that most men can already pass it off as a wedding band. For women, on the other hand, it's still a pretty obvious conversation starter. 

With the $400 Oura Ring 5, the company practically delivers on the fantasy of invisible technology hidden inside jewelry. And this alone may be worth the extra $50 above the price of the Oura Ring 4.

Easy on the eyes and finger

At 6mm wide and 2mm thick, the Oura Ring 5 is still larger than my actual wedding band, but it feels dramatically smaller on the finger. Oura says it's 40% smaller than its predecessor, and next to my Ring 4 and the Ultrahuman Ring Pro I'm currently testing, the difference is blatantly obvious.

It's also a subtler, more realistic shade of gold now: less costume jewelry, more fancy night at the symphony gold. Oura also added deep rose to its lineup, a rich copper-toned finish that joins the existing silver, black, brushed silver and stealth options in sizes 6 through 13.

Because I already owned an Oura Ring, I took a gamble and ordered a size down from my previous model (size 8). My Ring 4 was a size 9 that I mostly wore on my middle finger. This time, I wanted something that fit comfortably on my ring finger for side-by-side testing.

The size was a perfect fit for me, but I'd still recommend using the sizing kit, as Oura suggests, just to be sure.

Comfort-wise, the improvement I noticed first came while washing my face. The slimmer profile of the Ring 5 tucks more naturally under the folds of my fingers and doesn't drag across my cheeks and forehead while washing. I haven't taken it to the gym yet, but I suspect the same improvement will carry over to weightlifting, where previous smart rings often pinched into my finger.

Weight-based workouts are also the main reason my Gen 4 looks like it lost a fight. Scratch resistance is one of the Ring 5's key promises, though it's too early to call. What I can say is that after 48 hours -- including a brush up with the Pilates reformer -- it's still pristine. And I've definitely scratched tech on day one before, so that's a good sign.

Nighttime wear has also been effortless, and I don't even notice it throughout the night, though that was already one of Oura's strengths. I'll take a smart ring over a smartwatch or fitness band for sleep tracking any day of the week.

Sensors and accuracy so far

Because I was already in the Oura ecosystem and paying for the $6 monthly membership, getting started was seamless, and I picked up right where I left off.

Pairing took minutes, and Oura even gave me the option of keeping my older ring connected. I opted not to so I could isolate the Ring 5's sensors during testing.

Oura says it's reduced the number of sensor pathways on the new ring from 18 to 12 (likely due to size constraints), but says the LEDs are more powerful, in theory resulting in a stronger signal and more accurate readings. The company also claims better performance during movement and across different skin tones, both known weak spots for previous generations. 

Automatic workout detection also gets an upgrade across older models, too, which is particularly interesting because it has been one of my biggest frustrations with previous Oura Rings. Lower-impact workouts such as Pilates were often missed entirely. So far, my testing has produced mixed results.

The Oura Ring 5 still completely ignored a 30-minute late-night Pilates session, even though my heart rate climbed well above resting levels, peaking at 138 bpm according to my Apple Watch. Considering I'd already gotten credit for two separate "housework" sessions that were nowhere near as challenging, I was frustrated to say the least. That said, I'm willing to give it a few more shots. Oura says detection improves the more you tag consistently, so this will be one to revisit in the full review.

For the run test I left my phone behind and headed out for a 4-mile loop on around my usual route. The Ring 5 detected the workout and logged the exact start and end times down to the minute. The lack of on-board GPS meant it couldn't track distance, but heart rate data was impressive. Compared with my Apple Watch, which tracked almost identically to a chest strap during our testing, the Ring 5's maximum heart rate was just two beats lower (171 bpm versus 173 bpm) with identical average heart rate. Thats no small feat for a device this size. 

Sleep tracking has been spot on, too. Both nights matched my actual bedtime window almost perfectly, logging roughly 6 and a half hours of sleep and accurately capturing overnight interruptions. My readiness score, however, seems a little optimistic. The Oura gave me an "A-" this morning, despite my foggy brain insisting otherwise.

Temperature variations are also tracking as expected and continue to be one of the most useful features in the Oura app. Seeing how it correlates those fluctuations with my menstrual cycle data to pinpoint the exact moment of ovulation and therefore accurately track hormonal changes is, for me, one of its strongest selling points. 

The ring also monitors breathing variations, blood oxygen, heart rate and HRV, and now includes alerts for possible atrial fibrillation and sleep disturbances indicative of sleep apnea, though I need at least a week of data before those new features are unlocked.

Battery improvements are still TBD

After 48 hours of wearing the ring, I'm sitting at about 80% battery with an outdoor run and two nights of sleep tracking logged. That's well in line with Oura's promise of six to nine days, depending on ring size. The extra day compared to the Gen 4 is a welcome improvement (especially considering the slimmer band), even if competitors like Ultrahuman and Whoop are now stretching toward two weeks of battery life between charges.

So far, so very good

I was already a fan of Oura's app and the way it interprets health data, and the Oura Ring 5 builds on that foundation with a design that's significantly more comfortable and stylish to wear.

The fact that my strongest reaction after 48 hours has very little to do with sensors or health metrics probably says everything. Oura finally made a smart ring that feels like jewelry first and technology second.

The full review will determine whether the performance lives up to the promise, but so far, the Ring 5 is making a very strong first impression.