Holding on to a traditional timepiece no longer means missing out on modern fitness tracking. Chicago startup Ganance has unveiled Heir, a coin-sized sensor that adheres to the back of virtually any watch and quietly adds step counting and basic activity insights—without the bright screen or chunky smart case that can clash with a classic Rolex, Omega, or Grand Seiko.
Think of it as a stealth upgrade: keep the watch you love, gain the data you actually use, and leave the “tech look” to everyone else.
A Sensor Built For Purists Who Prefer Classic Watches
Heir is small and light—about 30mm across, 3mm thick, and just 5g—so it sits unobtrusively on the caseback. It attaches via a microsuction disc rather than a magnet, a critical distinction for mechanical-watch fans. Watchmakers routinely warn that magnets can disturb a movement’s delicate hairspring; Heir’s design avoids that risk while keeping the unit easy to remove and reapply.
Once in place, the sensor tracks steps, estimated distance, and calories. The company’s app presents the data in a simple dashboard, and iPhone owners can also sync to Apple Health. An Android app is planned, with compatibility for Google’s Health Connect so your metrics can flow into leading fitness platforms.
Controls are intentionally minimal. A single tap handles media play or pause; a double tap skips tracks. Calls and texts trigger a subtle vibration, with three intensity levels set in the app. If you want the fullest “invisible” experience, you can disable tap inputs altogether and let Heir quietly collect your movement in the background.
Fitness Basics Without The Bulk Or Distraction
Heir focuses on the everyday metrics most people actually check. There’s no heart-rate sensor or GPS, which keeps the form factor trim but also means distance is inferred from step data and personal profile settings. That’s typical for compact wearables; researchers at Stanford Medicine have noted that energy-burn estimates across wearables can vary widely, while basic activity counts tend to be more reliable. Treat the calorie number as a trendline, not a lab readout.
Ganance says upcoming software updates will add deeper context, splitting movement into “Active” and “Casual” categories and tracking sedentary time. The roadmap also includes adaptive goals, a silent alarm, expanded app notifications (including popular messaging and collaboration services), task nudges, and weather-based activity prompts. In other words, the brain keeps getting smarter while the watch on your wrist stays delightfully analog.
Why Discreet Wearables Are Having A Moment
There’s a sizable audience for health insights without a glowing rectangle on the wrist. Pew Research has reported that roughly a fifth of U.S. adults use a smartwatch or fitness tracker, but there’s an equally vocal contingent that values simplicity, privacy, and style. Rings and strap-on sensors (think Oura or Whoop) have proven there’s strong demand for low-profile tracking; Heir adapts the idea specifically for watch traditionalists who won’t swap a mechanical icon for a mini phone.
For luxury-watch owners, discretion isn’t just aesthetic—it’s practical. A thin, nonmagnetic add-on that hides under the caseback preserves comfort, avoids interference with the movement, and keeps attention on the watch itself. That’s a fundamentally different proposition than wearing two devices or compromising on design for the sake of data.
Battery Life Trade-Offs And Real-World Use
Heir’s main compromise is endurance. The sensor lasts about 42 hours per charge, which is shorter than ring or band trackers that often stretch several days. If you’re used to winding a mechanical once a day, topping up a tiny tracker might not feel onerous, but frequent travelers and marathon weekenders will want to plan around the charger.
On the wrist, the 3mm lift won’t bother most wearers, though ultra-snug bracelets or thin leather straps may require a quick fit check. For days when you leave the watch in the safe, Ganance sells an optional Heirband so you can keep logging activity without changing your routine.
Price And Who It’s For Among Watch Traditionalists
Heir is available for preorder at $149. The Heirband accessory costs $39, or you can bundle both for $169. That positions Heir well below full-fledged smartwatches while offering the essentials most people care about—steps, gentle nudges, and basic media control—delivered in a way that respects fine watchmaking.
If you want ECGs, maps, or multiday battery life, a dedicated fitness watch still makes sense. But if you’ve resisted wearables because they upstage your timepiece, Heir flips the equation. It lets the watch stay the hero, quietly adds the smarts you’ll actually use, and disappears under the caseback as if it were never there.