Sigma cares about your perfect fit.
We understand: a smart ring should not only work flawlessly but also feel comfortable on your finger and look stylish.
That’s why we made the sizing process as simple as possible:
Take a thin thread or a strip of paper.
Wrap it around the finger where you plan to wear the ring.
Mark the point where the ends meet.
Flatten the strip and measure the length with a ruler — this is your finger circumference.
Divide that number by 3.14 (π) → you’ll get the diameter. Compare it with the sizing chart.
Example: circumference 57 mm ÷ 3.14 = 18.1 mm → corresponds to size #8.
IMPORTANT
If you’re unsure, we’ve made it easy — simply order a sizing kit.
It will help you determine your perfect size with no risk of mistake.

The Sigma Ring can be worn on any finger of either hand. However, for the best signal quality, we recommend wearing it on the index, middle, or ring finger of your non-dominant hand — the blood vessels there are usually larger, which allows for more accurate pulse measurement using photoplethysmography (PPG). At the same time, the ring does not interfere with everyday activities.
The ring should fit snugly but comfortably. We recommend using the sizing kit to find your perfect fit.
For greater accuracy, wear the calibration ring for at least 24 hours, including during sleep, before determining your final size.
If you’re between two sizes, choose the smaller one — it will provide a more secure fit.

The standard set includes: Smart ring, Charging dock, Power cable. Additionally, you can purchase a sizing kit.

A fully charged ring provides up to 5–7 days of operation. This indicator is determined by the selected functions and intensity of use.
The actual operating time and number of charging cycles may vary, depending on the following parameters:
- ring size;
measurement frequency;
user activity;
battery age;
operating conditions;
individual settings and usage style.
A full charge of your ring takes from 20 to 80 minutes, depending on the current battery level.

Yes, you get a 1-year warranty.

Yes, the app is available in both languages. You can choose the one that’s most convenient in the settings.

Yes, you can. However, if you wear the ring only during sleep, some data about your daytime activity will be unavailable. This may affect the overall statistics, as only nighttime indicators will be taken into account.
To receive the most complete and personalized data, we recommend wearing the Sigma Ring around the clock — both day and night — removing it only in situations for which it is not intended, in accordance with the user manual.

The ring has a protective coating that increases its resistance to wear and minor damage.
However, with active use, traces of friction may appear on the surface. To maintain the impeccable appearance of the Product, we recommend following these simple rules:
- Wear the ring on your non-dominant hand (the one you use less).
- Avoid direct contact with other jewelry, abrasive surfaces or metal objects.
- Take off the ring during exercise, associated with high loads or friction (for example, lifting heavy objects, working with tools).
Clean your ring regularly with a soft, lint-free cloth. If necessary, the fabric can be slightly moistened with water. This will help remove traces of dirt and maintain the shine of the coating.

The ring has a water resistance rating of 5 ATM, which makes it resistant to water during everyday use.
You can wear it while taking a shower, swimming, or engaging in non-aggressive water sports.
Important: avoid prolonged contact with salt water. The ring is not intended for use during diving (deep-water immersion).
The ring remains functional at temperatures ranging from –10 °C to +35 °C (14 °F – 95 °F).
After any contact with water, it is recommended to wipe the ring with a soft cloth. This will not only help maintain its appearance and extend its lifespan but also prevent possible skin irritation on the fingers.

Sigma Ring is not a medical device and is not intended for the diagnosis, treatment, or prevention of diseases.
The ring is designed to track the dynamics of indicators and support a mindful approach to health and well-being.
Before making any changes to your diet, physical activity level, or medication intake, be sure to consult a doctor or other qualified specialist.

For proper operation and synchronization with the Sigma app, you’ll need a smartphone running iOS 14 or higher or Android 13 or higher.