A seemingly good-on-paper ring, the Circular Ring Slim is designed as an upgraded, budget-friendly version of the Circular Ring Pro. The features on this tiny and affordable ring are impressive, but did they make the cut to having me wear this ring 24/7?
With an accompanying app that I can only describe as “complicated” at best, here’s why you should skip the Circular Ring Slim and find a better smart ring for yourself.
Specifications:
| Specifications | Circular Ring Slim |
|---|---|
| Weight | 2g |
| Dimensions | Width: 8.8 mm, Thickness: 2.2 mm |
| Material | Exterior: High-grade alloy of matte black bead-blasted aluminum and carbon fiber. Interior: Medical grade nonallergenic, nonmetallic, and comfortable inner material |
| Sizes | 8 sizes: From US 6 to US 13 |
| Colors | 2 colors– black and silver |
| Battery life | Up to 5 days |
| Charging time | 45 minutes |
| Charger | Portable |
| Compatibility | Android 6.0 or later, and iOS 11.0 or later |
| Warranty | 1 year |
| Waterproof | IP68 |
| Memory | Up to 20 days of data |
| Vibration | Yes |
| Price | With vibration– $325 Without vibration– $226 |
| Subscription | No |
Design
The Circular Ring Slim is one of the slimmest smart rings I’ve worn. The one I tested out was black with no vibrations; therefore, only had two metal pins sticking out for the charger to stick to.
The sensors were not visible or poking my fingers, even if they had gotten a little swollen during a workout. However, I wasn’t the most pleased with the look of the ring. It looks like a basic fitness ring with a white circle logo on top, which to me looked more like an engraving at the time of purchase.
With only the comfort being a selling point for me, the ring by itself looks cheap and not well built.
Battery Life
While the claims are of a battery life of up to 5 days on a single charge, I’m afraid the only thing the Circular Ring Slim stands up to is its name. It barely lasted me 3-4 days on a single charge, which is way less than any other smart ring I’ve tried.
The ring has two modes– Performance and Eco. Now, I would use the Eco mode in order to save battery; however, it doesn’t do anything in Eco mode which a smart ring is used for. The sleep stages aren’t recorded, it limits the performance of the heart sensor and other metrics collected.
Features:
- 24/7 heart rate, morning resting heart, heart rate variability tracking
- Breathing rate
- Temperature
- Menstrual Cycle tracking
- Blood oxygen
- On-demand measurement for
- HR
- SpO2
- HRV
- Activity intensity
- Max HR
- Alarm clock
- 24/7 activity tracking
- Sleep tracking
- Guided breathing
- Timer and Alarm
- Airplane mode
- Recommendations
- Stress
- Vital alerts
- Energy monitoring
- Medication
- Sport tracking
- Advanced analytics
- Coherence
Sensors :
- 1 infrared LED sensor
- 1 red LED sensor
- 1 green LED sensor
- 3 axis accelerometer
- 1 surface temperature sensor
Sleep and Health Tracking
The Circular Ring Slim gives fairly basic sleep tracking along with a sleep score. The issue with this sleep score is that the metrics it is based on are not measured correctly.
There is a major syncing issue with the ring to the app, and the detection of sleep is way off. It will start recording the onset of sleep with the slightest of rest, and movements as multiple times of restlessness.
This resulted in a major percentage of my sleep disturbances and, therefore, a highly incorrect sleep score. The app also displays the data in a line graph format, which I found very inconvenient, especially if I wanted a quick look at my sleep for the night before. For a smart ring, the sleep tracking on the Circular Ring Slim is highly disappointing.
Additionally, the ring shows metrics such as stress levels, heart rate, heart rate variability, resting heart rate, skin temperature, blood oxygen, and breathing rate. Though the lineup of these features and metrics is quite impressive for a budget-friendly smart ring, it failed to make this data reliable.
Activity Tracking
The activity tracking on the Circular Ring Slim is, again, very basic. The ‘Heart Rate During Sport’ tracks a few exercises. I can also check activity intensity, steps, and total calories burned for the day.
I didn’t try it much at the gym, but even for my long walks and runs, even the step count was hilariously inaccurate.
With all the basics it provides, the Circular Ring Slim could have benefitted from additional data from third-party apps such as Strava or Nike Run Club, alas, that is not the case. It does, however, sync to Apple Health on iOS and Google Fit for Android devices.
There is also a VO2 Max score present under ‘Energy Analysis’, along with recovery, temperature, balance, and sleep quality, all depicted in line graphs, which, honestly, I don’t have time to look over. I need data that I don’t have to spend more than 5 minutes to interpret.
Syncing Issues
In a world where convenience takes the crown, the Circular Ring Slim lacks the race of the smart rings. The syncing between the ring’s data to the app is painfully long, which is not just my case. Multiple reviews have stated the same experience, with a few complaints of the ring just not connecting to the app, resulting in resetting it many times. This is not a good look on Circular.
AI Insights: Useful or Misguided?
The Circular’s AI, Kira, chimes in after a period of two weeks with insights and recommendations. These are personalized to my data calculated by the ring but were pretty generic in nature, like the ideal time to get some sunlight and hit the bed.
That being said, it did offer recommendations based on previous days’ data, which were helpful, especially since the history of the data is hidden somewhere in the app, and the current data shown is difficult to interpret.
Price and Subscription
The Circular Ring Slim has two models– one without a vibration (the one I tested), priced at $225, and one with vibrations, priced at $324.
Final Verdict
Apart from the slim design of the ring and maybe some of the AI recommendations, there is nothing I really found appealing about the Circular Ring Slim.
The app is confusing and not user-friendly; the previous data can’t be accessed properly, and it takes a long time to sync the data. For the amount Circular is asking for its Ring Slim, I know much better areas to invest my money.
If there’s one takeaway from this review, let it be this– invest your money on other smart rings in a similar price range, because the Circular Ring Slim has a long way ahead of itself.
