Fitbit Air can pair with analogue watches using a shared wrist strap

Fitbit Air users can pair the screen-free fitness tracker with a traditional analogue watch by threading its band beneath the watch, keeping the watch face visible and the sensor on the underside of the wrist. The approach lets people combine familiar watches with activity tracking without wearing separate devices on each wrist.

The tracker costs $99.99 and records heart rate, exercise and sleep, with data shown in the Google Health app. Its standard 18mm band suits watches with 18mm lugs; other widths may leave gaps or not fit, and some users have made 3D-printed adapters to retain their existing straps. Google recommends wearing the tracker on top of the wrist for best accuracy, so readings underneath are uncertain; comfort, water exposure and adapter security are also practical concerns.