💍Circular SLIM — Resurrection?

The French brand Circular has a very tarnished reputation. Just browse the forums on reddit and you’ll find all sorts of things — long…

💍Circular SLIM — Resurrection?

The French brand Circular has a very tarnished reputation. Just browse the forums on reddit and you’ll find all sorts of things — long delivery delays, poor quality HW, server outages (i.e. Circular apps not working), trivial customer support communication, refund issues, etc. Add to that the big Kickstarter successes of competitors (Ultrahuman, Muse One Ring, Iris/Velia, etc).

This could have gone one of two ways:

  • Extinction,
  • Bouncing back from the bottom.

But Circular clearly isn’t giving up and is opting to try and bounce back from the bottom. A few days ago, the news was revealed that we’re going to discuss briefly today.

(Old) new product

I think everyone familiar with the Smart Rings has been waiting for a brand new version of the ring. That is, a replacement for the existing Circular Ring. Atypically for the Circular Ring, it underwent changes during the development process, so it depended a lot on which stage you acquired the ring, see below an attempt to summarise the different variants.

However, different versions suffered from different ailments:

I received my version, which I have reviewed (see below), in December 2022. The ring still works, but most of the time it rests and waits for the occasional opportunity.

Circular ring — full review
Some time ago, I published an article on the topic of a paper comparison between Circular Ring and Oura Ring 3. Now I…

For the above reasons, I thought the company would ditch the old “Circular Ring” brand/version and come up with something completely new. This has only partially happened. Apparently, Circular has decided that it has fine-tuned its main product enough to continue offering it under the Circular PRO label, and is launching a new product to go with it called Circular SLIM.

The fact that SLIM is thin needs to be marketed properly, of course 😉

Full Specifications

Below is the full specification from the Circular website, including the classic highlighting of what Circular has over the competition on paper.

What does it mean?

Several things can be deduced from the specifications and the pictures:

  • Circular has probably managed (at the expense of the battery, among other things) to reduce the thickness of the ring to 2.2 mm. But beware: this is measured at the narrowest point, which is also the thickest point. The thicker part of the ring is hidden on the inside of the palm. This goes hand in hand with the lower weight. I’m afraid the battery life quoted is in the ECO mode of the ring. The question is how long the SLIM version will last in PERFORMANCE mode…
  • The concept of HW buttons and outer shells is retained within the PRO version. Hopefully they have tweaked both elements enough.
  • On the other hand, the SLIM Shells are missing, which I think is not a bad thing. And the physical button has been replaced by touch controls. That’s perhaps a pity. The key is the main element that distinguishes the Circular from all its competitors. I won’t go into the user-friendliness of the touch controls just yet.
  • There are also a few minor inaccuracies compared to others, for example, Ultrahuman AIR calculates VO2max, RingConn offers live readings, etc.


Circular now offers a SLIM version at a special price (until the end of November 2023).

💍 Circular SLIM (I haven't tested yet) for 215 € here

The acquisition, however, amounts to a lottery, as no mortal has seen the product yet. A small promise may be that the Circular app has finally (after perhaps two years) emerged from beta.

I was also intrigued by a post from one of Circular’s co-founders, which is quite candid. In short, they were in trouble for a long time, didn’t communicate to focus on development and now there are glimpses of a better tomorrow 🌅.

We will see…

Current BLACK FRIDAY Smart rings discounts

OURA 3 –40–100 EUR DISCOUNT — https://fitnesator.link/oura
CIRCULAR RING 8% DISCOUNT — https://fitnesator.link/circular
RINGCONN DISCOUNT code “BFD50EC126)” — https://fitnesator.link/ringconn
ULTRAHUMAN AIR DISCONT CODE -50 $ — https://fitnesator.link/ultrahuman