Jewelry-grade optical sensing

High-precision optical sensors read the pulse wave (PPG), HRV, SpO₂ and temperature straight from the wrist — a full health tracker built into a piece of sterling-silver jewelry.

Medical-gradeoptical accuracy
24/7HRV & SpO₂
Silver 925skin-safe design

A tracker you'd wear anyway

WITU · optical

Sensors set in silver

Sterling silver 925, natural agate stones and a butterfly tensioner turn precision optics into jewelry — PPG, HRV, SpO₂ and temperature, read cleanly and worn 24/7.

Medical-grade optical accuracy
HRV, SpO₂, temperature 24/7
Live human concierge, no subscription

Whoop · Oura · plastic optics

A sensor puck, not jewelry

The same optical principle — an LED reads the pulse wave — but housed in plastic or resin, tied to a monthly subscription, and with no path to real ECG when you want it.

No precious-metal jewelry design
Subscription required
No ECG anywhere in the lineup

Optics set in silver

Optical sensors on the wrist

High-precision optical sensors sit against the skin and read the pulse wave (PPG), HRV, SpO₂ and temperature 24/7.

Silver butterfly tensioner

A sterling-silver butterfly tensioner holds the sensors snug against the wrist, so the optical read stays clean through the day.

Agate stones pass the signal

Natural agate stones let the Bluetooth signal through without interference — jewelry and antenna at once, syncing every metric to the app.

DCI — how much you can trust the data

Inaccurate data leads to inaccurate advice. DCI shows how reliable the conclusions are right now.

DCI = sensor accuracy × 0.4 + blood tests × 0.3 + duration × 0.3

40%Sensor accuracymedical-grade optics

30%Blood testsbiochemical context

30%Durationhistory of observations

A user with a basic optical watch starts at DCI ≈ 60%. By pairing WitU's medical-grade optical read with blood tests — and, when they want it, an ecosystem ECG from the Patch or Chest Strap — they bring the index up to 100%, and only then do the recommendations become truly personal.

About the technology

How does the bracelet measure my health?

Through high-precision, medical-grade optical sensors. They read the pulse wave (PPG), HRV, SpO₂ and temperature straight from the wrist — a silver butterfly tensioner keeps the sensors snug for a clean read, and natural agate stones pass the Bluetooth signal to the app.

What is DCI?

The Data Confidence Index. It combines sensor accuracy (40%), the presence of blood tests (30%), and the length of observation (30%). The higher the DCI, the more accurate your personal recommendations.

Does WitU offer ECG?

Yes — across the ecosystem, not on the bracelet. The WitU Patch records continuous ECG at 500 Hz for up to 14 days, and the WitU Chest Strap uses dry ECG electrodes with 99.6% accuracy. The bracelet itself is a jewelry-grade optical tracker.

Is the bracelet comfortable to wear all day?

It's built as jewelry: sterling silver 925 — a skin-safe precious metal — natural agate stones and a hypoallergenic medical-grade strap, available in several colors. Comfortable enough to wear 24/7, so the optical sensors capture HRV, SpO₂ and temperature around the clock.

References

Claims about optical measurement and HRV rest on peer-reviewed research.

Bent B. et al. Investigating sources of inaccuracy in wearable optical heart rate sensors. npj Digital Medicine, 2020.
Schäfer A., Vagedes J. How accurate is pulse rate variability as an estimate of heart rate variability? International Journal of Cardiology, 2013.

Deeper into the science

See how medical-grade optical sensing translates into real health insights, or explore WITU's scientific basis.

Explore health Scientific basis

WITU is a wellness device, not a medical device

Insights are provided for general wellness and informational purposes only and are not intended to diagnose, treat, or replace professional medical advice. If you have any health concerns, consult a qualified healthcare provider.