Lumen

Added Sep 1, 2026

Lumen is a handheld breath sensor that estimates whether you are burning fat or carbs, with an app membership around the device. The shop sells the tracker and a renewing membership.

Price: Paid. On October 17, 2026 the shop listed the tracker at $349, marked down from $448, with 12 months of membership included and renewal at $149 a year. That markdown was presented as a limited-time offer.
Platforms: Hardware

Price source · checked 2026-10-17. Regional app-store prices can differ.

Where it fits

Wearables and health data · rank 06
A metabolism breath test, not a 24/7 wearable. Buy it for that one question, not as a replacement for a ring or a watch.

Pros

It measures a breath, which is a different signal from a heart-rate strap.
The device price and the renewal price were both on the shop page.

Cons

The $349 price was a promotion. The crossed-out price was $448.
You have to breathe into a gadget. It does not track a run or a workout on its own.