Ganance's Heir sensor redefines smartwatch integration for traditional watches with a reversible, damage-free attachment

Chicago-based Ganance introduces the Heir, a coin-sized sensor that attaches unobtrusively to traditional watches, bridging the gap between mechanical and connected wearables without altering watch design, promising enhanced health, notification, and media features.

Chicago-based Ganance is trying to bridge a gap that has long separated mechanical watches from connected wearables. Its Heir device is a coin-sized sensor that attaches to the back of an existing watch and adds smartwatch functions without changing the watch’s visible design, according to the company’s reservation page.

The system uses microsuction, a surface technology built around thousands of tiny air pockets, to hold the module in place without magnets, tools or adhesives. Ganance says that approach is intended to avoid damage and residue, while still allowing the device to be removed and moved to another watch. The company says the Heir works with most modern flat or slightly curved casebacks and is best suited to watches wider than 34mm.

Once fitted, the sensor tracks steps, activity and calories, then syncs the data to the Ganance app and to Apple Health or Google Health Connect. It also supports haptic alerts for calls, texts and app notifications, plus tap-based media controls. An Apple App Store listing says the app also provides distance and active-minute tracking and is free to download on iPhone.

Ganance says the Heir is a one-time purchase rather than a subscription product. The price is $149, with the company saying battery life is up to 42 hours and charging takes about an hour through an included USB-C dock. According to Ganance, shipping was expected in mid-July 2026, with limited pre-order availability still open, while the company also offers a separate HeirBand for users who want to wear the sensor on a strap during workouts or downtime.