# Polar is building a successor to a nine-year-old chest strap

Source: https://idevice.com/polar-is-building-a-successor-to-a-nine-year-old-chest-strap
Published: 2026-08-20

> The H10 has been the reference heart-rate strap since 2017, the device other sensors get tested against. An H12 now sits inside Polar Flow's code as a registered sensor, with placeholders still in it.

Polar Flow 7.36.2 arrived described by Polar as a minor update that fixes connectivity issues. Gadgets and Wearables went through it anyway and found an unreleased product inside: a device specification class named PolarSensorGardener carrying the names Polar H12 and H12.

A name in a string table is thin on its own. This is not that. The app identifies the H12 as a heart-rate sensor, allows it to be registered as one, and includes it among the devices its own internal handling logic treats as published. H12 also appears in the sensor registration code beside H6, H7, H9, H10, Polar Pro, OH1 and Sense, and among the sensors that support Polar's Fitness Test. That is four separate places in the app treating the device as real.

Parts of the Gardener class still look unfinished, with placeholders where values will go, so this is code Polar is working in rather than code it is about to ship. There is no date, no price and no specification anywhere in the find.

The H10 is why this matters more than a model number usually would. Polar shipped it in 2017 and it became the thing other heart-rate sensors are measured against, the strap that turns up as the control in accuracy tests of watches and rings that cost five times as much. Nine years is a long time to leave a reference device alone, and a successor to it is a bigger event for the people who care about heart-rate data than most watch launches.

What a chest strap has to do has not changed in that time, which is the awkward part of replacing one. It reads the electrical signal of a heartbeat directly, which is why it beats the optical sensors on a wrist, and there is no accuracy left to win. Any H12 has to justify itself on battery, connectivity, or what the sensor can do besides count beats. The Fitness Test support sitting in the code says at least the third of those is on the table.

Polar has announced nothing, and its own release notes for 7.36.2 say it fixes connectivity issues.