About halfway through the trailer for the 2011 movie Green Lantern—it's presumably in the movie, too, but that's impossible to verify because no one ever saw it—an otherwise ordinary Ryan Reynolds slides a big, blocky ring onto his middle finger and becomes a superhero. "The ring," says an apparently important dying purple man, "It chose you. Use its power to defend our universe." It's the other one ring to rule them all.

Sonia Hunt's goals for her smart ring are, let's say, slightly more mundane. She's the president of Neyya, which sells a chunky ring meant to be worn on your index finger. It's meant most squarely for traveling, presentation-giving execs tired of re-wiring entire office buildings just to get their PowerPoint remote to work. The Neyya ring works via Bluetooth, and all you have to do is discreetly swipe on its glassy face to scroll between slides. It does lots of other things, too, like control your music and alert you to important incoming calls. But its primary superpower is in the boardroom. It's the PowerPoint Punisher. The Keynote Knight.

Neyya is one of a number of companies that has decided there is no "wrist" in "wearable." They've skipped smartwatches and fitness bands, and set their sights on your fingers. In a sense, smart rings are everything we want wearables to be. They're jewelry first and gadgets second. They're subtle in a way looking at your Apple Watch can never be subtle. They're easy and natural to use, and they become a part of you the way your wedding band does. Until truly great natural-recognition gesture tech catches on and we get RFID chips embedded in our forearms, rings could be the closest thing to truly seamless technology. If they work right.

If.

First, smart ring-makers must grapple with the same existential question facing the Apple Watch, Google Glass, and every other shrunken computer we're being asked to put on our bodies: What is it for? Ring-makers have it even harder, because they can't just slap a touchscreen on your wrist, connect it to an app store, and hope developers answer the question. Rings are definitionally smaller and simpler; you don't have much room for anything other than a battery. Even those who can do everything realize they shouldn't.

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There's an unspoken arms race happening on crowdfunding sites as entrepreneurs vie to see who can make the most tricked-out ring. Mota's SmartRing shows you all your notifications and has a replaceable battery! The Smarty Ring does all that and controls your music! Aring Pro is like having Siri on your fingers! Logbar's Ring lets you text by writing in mid-air and scroll through Netflix queues with grand gestures! Put the Nod on your finger and control your drone! Only a few of these are real products. Most are vaporware. One (Logbar) was convincingly declared the "worst product ever made."

The Neyya began as a similar do-everything kind of device, hitting Indiegogo in 2014 as the Fin Wearable Ring. It didn't look like jewelry. It was more like a super-futuristic brace for your thumb. Put it on, and you could use your fingers as a game controller, a mouse and keyboard, a remote control for your car, a personal authenticator, and much, much more. It was created by five friends, all engineers in India, fascinated by gesture technology. "Their interest was in creating something that you're able to wear and control just on one finger," Hunt says. Every imaginable feature was fair game.

Fin raised more than $200,000 on Indiegogo and another $2 million in venture capital. Then it had to become a real company, with a real product. When Hunt and other seasoned pros came in, they started a true product development cycle. "You're kind of ripping apart your own product," Hunt says, "to see if it's the right one for the market." They realized that for all the cool technology, Fin wasn't a good product. Its battery didn't last long enough. It didn't look good enough. Your index finger is actually a much better place for it. And try as they might, users could never figure out how to use the thing.

After months of research and testing, the ring they came up with was so different it needed a new name—so Neyya was born. Just before it launched, news leaked that Apple had applied for a patent for a shockingly similar device. "A need ... exists," the application says, "for a more discreet, safer, more efficient, or more ergonomic way to interact with touch pads or touchscreens. " Now, patent applications don't mean anything in terms of actual products, but "that was huge validation to us," Hunt says. "That we did the right thing, we were thinking about it the right way."

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John McLear, on the other hand, has been thinking about rings in a completely different way. A developer and former WordPress employee, he started working on the NFC Ring as a simple authentication tool. He raised nearly 10 times his initial Kickstarter goal with a fairly simple promise: Your ring can unlock your phone or your front door, work as a bus pass, and even share information with other people. NFC is ridiculously simple to implement, and since it requires basically no power, you never need to take it off. It looks slightly nerdy and definitely masculine, but it looks like a ring.

The ultimate goal of every smart ring is the same as any other wearable: hide the technology invisibly within the jewelry. Only a few come even close, and only Ringly really gets it right. The Ringly ring is obviously meant for women, and is quite nice looking. I may not be the target market, but I like how the big hexagonal semi-precious stone makes me feel like a 1970s mafia don when I wear it on my pinky. The only obvious tech is a small LED on the underside of the stone, which I set it up so that calls from anyone on my VIP list cause the ring to vibrates four times and flash a subtle pink light. An email brings two buzzes and a yellow light. It's meant to keep me from missing important things while also slowly weaning me of the need to check my phone every time it buzzes. Ringly CEO Christina Mercado says it's far more useful for her. Her phone is never in her pocket, she reminds me. It's in her purse. "It’s something I have to point out to guys," she says, "because you know, you have pockets. You feel your phone vibrate—I don’t!"

Mercando never intended to make "a wearable." That phrase seems to unsettle her just a bit. Her goal, she says, was to make attractive jewelry that happened to be smart and useful. She wanted to make something she'd want to wear anyway—but never tried to make something she'd wear all the time. "You have to think of it more like clothing," she says, "where you don’t just buy one pair of shoes. You buy shoes that we wear to the gym, we buy shoes that we wear to a cocktail party, we buy shoes that we wear to work. And I think, you know, wearables are going to take the same path." Mercado says she's heard from designers and manufacturers of every stripe wanting to integrate her tech into their jewelry. Even companies that make class rings are interested. (Class of 2021, your rings are gonna be crazy.)

The wearable-as-notification-machine idea is a popular one—beyond fitness tracking, it's really the only compelling use case anyone's come up with. But how do you communicate information without a screen? Ringly, along with more traditional wrist-bound wearable companies like Misfit and even Apple to some extent, is playing with a combination of lights and buzzes. But Neyya's Hunt doesn't buy it. "I just can't even remember, like, if my mom's calling me and it's vibrating three times and flashing pink," Hunt says, "or my dad's calling me and it's vibrating five times and flashing blue." It was too much. "My Apple Watch, it has so many apps synced up with it," she says. "We just didn't want to get into any of that." Neyya purposefully doesn't do that stuff—if there's no way to do it well, Hunt says, don't do it at all.

So Neyya, like many other smart rings, has settled on a reduced set of features. Long-term, it has the same change-everything goals as so many other wearable companies, which want to use step-tracking and notifications to begin to change how we use and understand technology. But right now, for reasons both technological and psychological, the best wearables are the specific ones. Use this wristband while you run; let this light track your sleep and help you wake up in the morning; put on this ring before you give the quarterly update. Then take it off.