Kidde has become the best-known name in the world of smart smoke detectors—a relatively low bar given how few people know the brand of their smoke detector. Still, you’ll find Kidde recommended by reviewers and customers across the internet with surprising enthusiasm, which has only increased since the brand started collaborating with Ring and Amazon, making it an easy add-on to Alexa-powered smart homes.

Until now, if you wanted a Kidde smart smoke alarm connected to your other devices, one that would send you alerts by Ring app, you could only choose a hardwired model. Anyone who wanted something battery-powered from Kidde along the lines of the now-discontinued Google Nest Protect had to skip the smarts.

At the CES trade show in January, Kidde announced its first battery-only smart smoke alarm, once again in collaboration with Ring. The Kidde Ring Smart Smoke + CO Alarm has been available for preorder since the announcement, but as of today is fully available to buy.

How It’ll Work

Kidde’s Ring Smart Smoke + CO Alarm will use two AA batteries (included in the box). It’ll come with a mounting bracket for installation, and you can choose to mount it wherever you see fit, thanks to the battery flexibility. Kidde recommends not installing a smoke detector within six feet of heating appliances, less than four inches from an A-frame type ceiling, or in areas like garages or near things like lights, fans, vents, windows, and anything that could directly expose it to the weather.

Once it’s installed, you can connect it to your Wi-Fi and the Ring app. You won’t need any additional Ring technology—no hub is required, even though you’ll find one in most Alexa speakers these days—to have it work with the Ring app. Ideally, you’d already have an app and be a Ring user if you’ve chosen this smoke detector, but if you haven’t, make sure to get the app and set up your account.

Third-Party Smoke

Both Amazon and Google have chosen to partner with brands instead of making their own in-house smoke detectors. Google now partners with First Alert for a smart smoke and carbon monoxide alarm replacement after discontinuing the Google Nest Protect, and Ring both has this partnership with Kidde and can work with Z-Wave models from First Alert too.

It’s not a surprising move from Google, which has been moving to make less of its own hardware and instead place its smarts in other brand’s products. Amazon usually likes to make its own massive range of hardware, so it’s worth noting that if Amazon isn’t making this device itself, there’s a reason. It may be a poor investment to maintain such a specific line of products, or maybe because it’s hard enough to do well that the company would rather leverage someone else’s tech. Whichever reason—maybe both—if you’re shopping for a new smart smoke alarm, Kidde’s newest model is one to consider, especially if you have an Alexa household.

Power up with unlimited access to WIRED. Get best-in-class reporting and exclusive subscriber content that’s too important to ignore. Subscribe Today.

Other Smart Rings We’ve Tested

We have tested several other entrants in this category, some good, some bad, and some in between. Here is the lowdown on some of your smart ring alternatives.

Leep Ring 1 for $200: A new British smart ring that is affordable, subscription-free, and offers simplified, accessible stats on your activity, sleep, and stress? Sign me up. The Leep Ring 1 is slim and stylish, with a subtle diagonal indent to help you line up the knobbly internal sensors. It comes with a handy charging case that’s supposedly capable of providing an extra 60 days of charge. A fully charged ring is meant to last up to eight days. (I’ve been getting closer to five.) The app is straightforward (only available for iPhone right now, but there’s an Android app in the works) and gives you a big score out of 100 for sleep, balance (stress), and activity. Sadly, sleep is woefully inaccurate and tends to report that I’ve been asleep for my entire time in bed, even if I was watching TV or reading. Last night, it suggested I slept 8 hours 43 minutes (Oura says 6 hours 52 minutes). The activity and stress scores seem a bit more accurate, with step counts that were mostly within 100 or so of my Oura and Apple Watch (it was out by 1,000 one day). But the app could use some polish. For example, it doesn’t take into account that it’s only a couple of hours into the day before telling me my movement for today is “Bad.” I also lost data on the first night it ran out of battery, and there was no warning notification to tell me to recharge. It’s early days for Leep, and it’s priced very reasonably, but it needs to improve fast to compete.

Photograph: Simon Hill

Luna Ring 2.0 for $329: We had issues with charging and connectivity with the first-generation Luna Ring, but the Indian manufacturer seems to have made significant improvements in version 2.0. My Luna Ring 2.0 came with a jazzy wireless charging case (it is $29 cheaper with the regular charging dock) that promises up to 30 days of power. The ring is supposed to go five days between charges, but I found four was more realistic. I don’t love the diagonal crease that marks the front of the ring, and it’s not as comfortable as my Oura. It boasts all the usual sensor suspects for tracking (optical heart rate, blood oxygen, PPG, skin temperature). Data is divided into sleep, readiness, and activity tabs in the busy app, with the obligatory AI option for advice and insights. There’s no subscription necessary, which is a big plus, and the data seemed reasonably accurate, but it’s definitely on the generous side. Comparing a full day to my Oura, the Luna thought I got an extra hour of sleep, burned 100 kcal more, and rated my readiness above 80 out of 100, while Oura scored much lower and picked up on something straining my body (I do have a cold right now). If you want a subscription-free ring, I prefer the Ultrahuman listed above.

Photograph: Adrienne So

Circular Ring 2 for $349: This ring is pretty, with rounded edges that make it slightly look more like jewelry than the Oura or Ultrahuman rings. I also like the closed charging case, which means you can bring it while traveling and recharge without a USB-C cable, and I also like that the ring pings me throughout the day when I’m in my best zone for productivity, working out, or caffeine. However, during my two-week testing period, I was plagued with persistent server issues and data processing delays that made it difficult to double-check any of my health metrics for accuracy, like heart rate, SpO2, or sleep data. It also makes it hard to recommend this ring right now. I will hold onto it for now and see if this improves.—Adrienne So

Movano Evie Ring for $269: When it first came out, the Movano Evie Ring was touted as the world’s first fitness tracker designed specifically for women. I was very excited! It was recently updated to integrate with Apple Health (in the iOS version of the app), and you can now see your cycle day on your home page, manually log your basal body temperature, and manually add workouts. However, these new features are pretty underbaked compared to those offered by its competitors. Now that Oura and the Galaxy Ring can track periods so accurately, this ring’s time may have passed. But it’s relatively affordable, has no subscription fee, and has a blood oxygen sensor, so that’s kind of nice. —Adrienne So

RingConn Gen 2 for $299: Despite a price increase over Gen 1 below, this is still a relatively affordable, subscription-free smart ring. RingConn retained the distinctive squared-off design, but this second-generation ring brought major improvements to sleep tracking (including sleep apnea detection), better battery life, and is very slightly slimmer and lighter. I found basic sleep and health monitoring solid (sleep is much more accurate than the first generation), but workout tracking is still a major weakness. Despite more available exercise types, you must manually trigger workout tracking, and it struggles with accuracy at higher heart rates.

RingConn Smart Ring for $99: Now heavily discounted, the original Ringconn is worth considering. A slightly squared-off design with beveled edges gives it a unique look, the health and sleep tracking work well, and it lasts four or five days between charges. It also comes with a handy battery case (enough for several charges on the go). However, I had trouble with data syncing, the app lacked proper workout tracking, and the data was sometimes inaccurate, though the app is steadily improving through updates.

Amazfit Helio Ring for $200: Purveyor of affordable fitness trackers like the Amazfit Active 2, I expected a competitive smart ring from Amazfit, but the Amazfit Helio is badly out of shape. I like the subtly textured bronze finish, but it is the only color you get. Sizes are also limited to 8, 10, or 12 for now (sizes 7 to 13 are coming). While it has similar capabilities to the smart rings above, the Helio was sometimes hopelessly inaccurate, with heart rate measurements wildly out of step with other trackers. It lacks automatic workout-tracking, battery life averaged three days for me, and the Helio frequently disconnected from the busy and confusing Zepp app. You don’t need a subscription, but there is Aura AI ($70/year) for sleep insights and content or Fitness ($30/year), which includes an AI coach. They are expensive and confusing. (Why have two separate subscriptions?) The Helio works much better in conjunction with a smartwatch (I tried it with the Amazfit Cheetah Pro), as it can merge the data, but as a standalone device, it is impossible to recommend.

How Do I Choose the Right Smart Ring Size?

AccordionItemContainerButton

Some smart rings come in standard sizes, but there is variation, and half sizes are rare, so it’s worth taking some time to ensure you get the correct ring size. Most manufacturers will send you a free sizing kit, enabling you to wear a dummy ring for 24 hours. (You may have to buy the ring directly from the manufacturer to get this kit for free.) You should absolutely do this. Bear in mind that your fingers swell and shrink throughout the day. Your smart ring should be snug to enable the sensors to measure accurately, but you will have to remove it regularly to charge, so you don’t want too tight a fit.

Which Finger Should I Wear My Smart Ring On?

AccordionItemContainerButton

You can wear your smart ring on any finger, but most manufacturers recommend wearing these gadgets on your index finger, though the middle or ring finger can also work. These three fingers all have large blood vessels for more accurate pulse monitoring. What’s really important is that the ring fits tightly and securely around the base of your chosen finger, so if you have a big knuckle and a narrower finger base (more common with the middle or ring finger), this can be tricky. I recommend wearing it on the index finger of your less dominant hand because I found wearing it on my right index finger, as a right-handed person, led to more damage on the ring and scrapes on some things I touched.

Which Smart Ring Finish or Color Is Best?

AccordionItemContainerButton

All the smart rings we tested combined tough titanium with a sensor array on the inside, but the coatings and colors vary. If you are hard on rings, a silver or gold finish will likely suit you best, as there is less risk of damage. My Oura and Ultrahuman rings with black finishes have visible scratches and chips after a few months. Our Galaxy Ring test unit has been on a tester’s finger for more than a year, and the edges of the titanium black ring now look silver.

The Oura, Samsung, and Amazfit rings have tiny dimples to help you align the sensors. While I prefer the smooth finish of the Ultrahuman, I suspect correct placement aids accuracy enormously.

How Do I Care for My Smart Ring?

AccordionItemContainerButton

Most smart rings are durable, but if you want to avoid damage, you should remove your ring when working with tools, weight lifting, washing pots and pans, or even cleaning the sink. If your ring is likely to rub against a surface, take it off. I found this was a bigger problem wearing a ring on my index finger than with the middle or ring finger. I scratched the Oura and Ultrahuman rings when gardening, moving boxes, and using a dumbbell. Titanium is also tough enough to damage surfaces in your home. I gouged the porcelain of my sink and marked the inside of a mug with the angular Ringconn. All the smart rings we tested are water resistant, so you can swim or shower without taking them off.

How Often Do I Need to Charge My Smart Ring?

AccordionItemContainerButton

Photograph: Simon Hill

Smart rings come with a charger and cable, but you will generally have to provide your own wall adapter. From dead, they take anywhere from an hour and a half to three hours to fully charge, but you should avoid letting the battery run down completely, or you run the risk of losing health data. We tested the smart rings above with all the bells and whistles turned on, so our battery life estimates are lower than the manufacturer’s claims.

What Smart Ring Features Should I Look For?

AccordionItemContainerButton

Most smart rings will track your sleep, heart rate, and temperature. If you want to keep an eye on your sleep and get health insights unobtrusively and comfortably, smart rings are ideal. Fitness tracking varies, with most smart rings offering basic step counts and movement, some offering manual workout tracking, and others offering automatic workout recognition. But you can expect more depth and accuracy from a traditional fitness tracker or smartwatch. Combining a smart ring with an Apple Watch or Fitbit makes for a seamless experience, allowing you to take off the watch and let it charge at night without gaps in your tracking.

Smart Rings or Smartwatches?

AccordionItemContainerButton

In the past few years, we’ve fielded many questions about why someone would get a smart ring instead of, or in addition to, a regular fitness tracker or smartwatch. Here are a few reasons why you might consider it:

Better battery life. A smart ring is smaller and usually (if not always) has better battery life. It’s a helpful addition to your repertoire if you hate missing a couple hundred, or a thousand, steps while you’re charging your smartwatch every day.

Sleep tracking. It’s no coincidence that our favorite sleep tracker is a small, unobtrusive ring. Maybe you’re tired of having your enormous Apple Watch Ultra smack you in the face every time you turn over. (Or maybe you’re charging it instead!)

Cycle tracking. Many watches and fitness trackers now feature a skin temperature sensor that’s sensitive enough to detect when you’re sick or drinking alcohol. However, in Adrienne’s testing so far, only the Samsung Galaxy Ring and the Oura have been accurate enough to track her menstrual cycle.

Finally, fashion. Watches are a statement and a status symbol; a smartwatch often says nothing more about your preferences and choices besides “I don’t like missing meetings.” Almost everyone we know who has bought a smart ring has done so because they have a hand-me-down Cartier Tank, or a fun Casio or Swatch, that they don’t want to give up. If this is you, good for you! And get a ring!

AccordionItemContainerButton

We have been wearing smart rings continuously for several years (sometimes two or three at a time), so we have a good handle on what makes a smart ring worth buying. Every smart ring we test has been worn for at least a month, usually longer, and we always compare its tracking data against our top pick (Oura) and with other smartwatches and fitness trackers (Apple Watch).

AccordionItemContainerButton

We are re-testing the Circular Ring 2 and the upcoming RingConn Gen 3.

Power up with unlimited access to WIRED. Get best-in-class reporting and exclusive subscriber content that’s too important to ignore. Subscribe Today.

The grifters, according to RentAHuman, are fading. “We’re taking safety extremely seriously,” Liteplo says. But the duo also acknowledge that there are “footguns” (features that often lead to pesky bugs) and have implemented paid verification (at $10 a month), inspired by Elon Musk’s strategy of letting users pay $8 to get a “verified” badge on X. “He’s my entrepreneur hero,” Liteplo says, unabashedly. “For Twitter, they had a bot problem and they still have it, but he mitigated it a lot by making it pay-to-play. The unit economics of scammers disappears,” he continues.

(Musk tweeted in 2023 that “paid verification increases bot cost by ~10,000% & makes it much easier to identify bots by phone & CC clustering.” No official data exists on a reduction in bots since the introduction of the $8 blue tick, but X’s subsequent purge of 1.7 million bots in late 2025 suggests that the site was not purged by paid verification.)

For now, any major pitfalls seem to be mitigated by the relatively small number of tasks being commissioned on RentAHuman. There’s a huge labor surplus: over half a million rentable humans are signed up and ready to complete tasks, but only 11,367 “bounties” have been posted by AI agents so far.

Firth-Butterfield questions the novelty. “Actually what is new? This is a website on which humans can sign up to do tasks and get paid for doing them,” she says, comparing it to TaskRabbit or Mechanical Turk.

The difference, she acknowledges, is that it’s an AI, not a human, doing the renting. But she emphasizes that there’s still interference from us meatbodies. “Currently, AI Agents are created by humans to do tasks which are prescribed for them, so the person doing the hiring is in the company which created the bot,” she says. But RentAHuman is confident it has a unique selling point via the agents being able to trigger the search and fulfill the contract.

Other veteran artificial intelligence experts are offering kudos for its marketing but not its mechanism.

“This seems like kind of a stunt at the moment. It’s hilarious—renting meatwads. But candidly, I’m not sure it’s worth either of our time,” says David Autor, professor of economics at MIT. Elsewhere, there are concerns that we’re not fully grasping the granular details of the situation.“We need to build AI literacy across our population so that individuals can see behind the rhetoric and hype,” says Firth-Butterfield.

For its cofounders, RentAHuman isn’t just a novelty or a stunt; it’s the next step in the inevitable timeline where AI takes over the labor market. There’s also mega potential, Liteplo says, to get “the best training data in the world” to feed to models (see: requesting videos of human hands).

“Dude, it’s genuinely scary, the implications of how many unique datasets that weren’t possible to [easily] collect before we have now just unlocked,” says Liteplo. And the team hopes potential investment will pay creative dividends. “We now have a blank canvas to do amazing, fun things and manifest all of these dreams in our heads into the world,” Liteplo says. After sharing the 10-year road map for RentAHuman with John Edgar, previously head of community at DeviantArt, Edgar reportedly told them: “You guys are going to build a terrifyingly large business.”