Smart rings are small and slim and for that reason alone, they can be difficult to get right. And while there have been some casualties in the world of smart jewellery, there's still a host of talented startups that prove you can make great fashionable wearables that live on the finger for both women and men.
Essential reading: Best smartwatches for women
We've picked out the smart rings we've enjoyed using and the rings on the way that you should definitely keep a look out for.
Got any questions about what we've included? Let us know in the comments below.
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Best smart ring: Motiv ring
Here's our fave. The iPhone (and now Android) compatible smart ring, Motiv, turned heads when it was announced in early 2017 and it's not hard to see why. It's sleek, just 8mm wide and comes in rose gold or slate grey finishes of titanium. Plus, there are seven sizes to fit both male and female fingers.
Inside, it's a fitness tracker that will monitor steps, distance, and active minutes, as well as heart rate thanks to an optical heart rate sensor. The battery will last five days and it's even waterproof to 50m. New Alexa support means you can check in on your stats as opposed to bark orders at your finger.
In our tests, we found it to be both stylish and easy to wear thanks to its light, comfortable form factor and it's rightfully the best option out there.
Wareable verdict: Motiv Ring review
This high end, sleep tracking and analysing smart ring raised a boatload of money on Kickstarter and became one of the few to actually ship to backers. The app uses data on how well you've slept and does something useful with it - Oura provides you with a simple, intuitive readiness score for the day.
Plus, it makes personalised suggestions and can show you trends over time - though in our testing we'd like to see more of this. Oura comes in three colours and ring sizes 6-13. In our review we noted that the design might divide opinion, but it feels luxury and the sleep tracking is really great.
Early backers are already taking advantage of the original Oura, but the new Oura Ring is starting to ship in April 2018. It looks suspiciously similar to the Motiv above, but those interested can pre-order the device in three different styles from a range of colours.
Read this: Oura Ring review
From $299, ouraring.com
The second-gen NFC ring, crowdfunded on Kickstarter, can be used to unlock phones and doors, transfer information and link people.
The ring packs two NFC tag inlays - one for public information and one for more sensitive stuff. The private tag - for things such as your smart door lock and payment information - sits on the inner part of the ring closest to the palm, so that it requires a deliberate gesture to use. The public portion, for stuff you want to give out, like your email address, sits on the top side of your finger.
Waterproof to 50m, the ring comes in a range of subtle designs, including ceramic coated in gloss black. So there's something to suit both men and women. And the best news? It never needs charging, and it's by far the cheapest option on this list.
A new OPN NFC ring is now also available and while it lacks the payment support, it does have a smoother-look design and improved compatibility with host of devices and digital door locks.
Blinq is a luxury smart ring collection that wants to keep you fit and safe and just recently launched on Kickstarter. It's the work of a Montreal-based startup and offers sterling silver and 12-karat gold rings with 12 styles and seven different gemstones to choose from.
Features wise, there's an SOS Alert feature that works by tapping a custom sequence to send a text to friends, as well as notification filtering via a special backlight behind the stone and basic activity tracking. Blinq started to ship its rings in February 2018.
From $119, kickstarter.com
Startup Sleepon believes there's still room for innovation in the sleep monitoring realms and it's hoping it can offer something new with its Go2Sleep smart ring.
The iOS and Android-friendly ring features a 3-axis sensor to monitor sleep and also features blood oxygen and heart rate sensors that will record data including perfusion index (pulse strength), heart rate and blood oxygen saturation. As far as unique sleep metrics are concerned, it claims to be able to even track your tossing and turning during the night.
The AI-powered app will offer personalised recommendations and Sleepon also claims it can help detect whether users are suffering from sleep apnea. It successfully passed its $20,000 target goal on Indiegogo and is in the production stage with shipping expected in May 2018.
ORII Smart Ring
We've got high hopes for ORII, which raised over $400k on Kickstarter in 2017. Its particular secret agent trick is that it lets you take calls by holding your finger to your ear, something we've seen on smartwatch straps before but which makes even more sense as a smart ring form factor.
It's available in matte black, sandblasted silver, metallic dark grey and armor red finishes and other features including getting voice read-outs of text messages and notifications, hearable-style without the earbud permanently in your ear.
Hong Kong startup Origami Labs was looking to ship the ORII in February 2018, but recent updates on its crowdfunding page suggest that has been moved to June 2018.
In-depth: We talk to Origami Labs about ORII