The Circular Ring Slim has been given a big overhaul – with new sleep algorithms, workout tracking and a new tougher build.
We reviewed the Circular Ring Slim back in February 2024, and while there were promising signs of a good product there – we had some reservations. In. Our review we found the ring scratched way too easily, criticised it for a lack of water resistance, and bugs in the software experience.
This update fixes many of those criticisms.
The hardware of the Ring Slim has been changed to use a smoother epoxy to boost scratch resistance and boosts water resistance to IP68.
On the software side, there are a host of improvements too, which will roll out to existing users.
There’s a focus on workout HR, with a new sport alogorithm. Users can track workout sessions from the finger and use their smartphone’s GPS to get location data for the session. There’s also a new sport ring goal within the app, which users can close to ensure they are hitting their targets.
The Kira+ app has also been give an overhaul with a new advanced analysis circle, which blends a host of biometric analysis into a single score – in a bit to boost usefulness and actionability.
And finally, the sleep algorithm has been overhauled.
This also addressed a major criticism of our testing where we found that “On some nights it suggested we had no deep sleep and also didn’t pick up we’d quite clearly woken up during the night. It meant that some sleep quality scores felt artificially high.”
Circular says that “the new sleep algorithm proved 79% accurate against polysomnography tests – the recognized and proven tests that are used to diagnose sleep disorders by recording brain waves, blood oxygen, and heart rate during sleep.”
With the smart ring market heating up, Circular is bringing these updates at a good time. They’re much needed, but could make its offering more appealing in the face of Oura, Ultrahuman, RIngConn and Samsung.
The Circular Ring Slim costs $281/£226 without a monthly subscription. So it’s well placed to be a player in the smart ring space.