Unlike other smart rings, it has a vibrate function too, enabling you to set alarms.
Think of it as a fitness tracker designed to collect data from your finger, rather than your wrist.
Data collected is presented as scores and charts in the accompanying app.
In fact, Id recommend sticking with one of thebest fitness trackers at least for now.
On paper, the Circular Ring Slim offers everything it needs to compete with rival brands.
It looks and feels decent, collects a variety of data, and offers genuinely useful insights.
But in practice, the Circular Ring Slim needs improving.
Released in early 2024, Circular has been taking pre-orders in batches.
Also competing for your attention in this space is the Ultrahuman Ring Air.
At the time of writing, it costs $349 (about 276 / AU$536).
Nevertheless, the Circular Ring Slim is comfortable to wear.
I wore it for most of the day over six weeks and didnt really notice it on my finger.
The interior is smooth enough not to irritate or pinch, and the ring is incredibly lightweight.
The matte black finish looks super slick when you first take the Ring Slim out of the box.
This isnt unexpected; I had similar issues with the Ultrahuman Ring Air.
The little white Circular logo is an unexpected design choice on the Ring Slim.
Compared to the Ultrahuman Ring Air and my Apple Watch, I found these to be accurate.
One unique part of the Circular Ring Slim offering is that it can vibrate.
Something in-between a smart ring with vibrations, for example felt different and unnecessary.
Although, Im aware this is likely to come down to personal preference.
Another feature that makes the Ring Slim stand out is what Circular calls Kira.
This is branded as an AI assistant that learns more about you over time to then offer personalized insights.
However, this isnt explained particularly well; youre simply told that for 14 days the ring is calibrating.
Importantly, once the calibration period had passed, the insights delivered were genuinely useful.
Although disappointing, this is standard with smart rings.
I’d need a separate gadget for that.
The one area where it struggled at times was sleep.
Over the majority of nights, the data the smart ring collected was accurate and useful.
However, any disturbances in the night appeared to throw it off.
For example, there have been occasions where Ive woken up at night around 4am for 15-20 minutes.
Several big issues affected the daily wear and use of the Circular Ring Slim, too.
The one that let down the unit, and me, most was battery life.
Note here that the ring features two battery modes.
Theres Eco, which offers infrequent heart rate tracking but no sleep insights.
Then theres Performance mode, which tracks everything, including sleep stages.
In this mode, the ring lasted only two days before needing a charge.
Often Id choose to charge it overnight, but this meant missing out on collecting sleep data.
Setting up the ring was relatively easy, but I did experience issues with syncing during testing.
That was accompanied by the question: What could this possibly mean?
which already sounds a little strange.
And Ive already mentioned the super wordy, long questions asked during the setup process.
In fact, on a personal note it would probably dissuade me from looking at my data.
Scorecard
Circular Ring Slim: Should you buy?
This rig doesnt deliver the slick and seamless experience you might expect.
In addition, in my opinion, the white Circular logo made it look cheap.
I also preferred the Ultrahuman app and found the sleep data more accurate.
This gave me a great opportunity to put it to the test outside my regular routine.
