TAG Heuer has been making precision sports chronographs since 1860, and named its smartwatch module the Calibre E4 - the same naming convention applied to its mechanical movements. The Connected Calibre E4 runs Wear OS on a sapphire OLED in steel 42mm or titanium 45mm, with an exclusive golf app covering more than 40,000 courses that no other Wear OS watch provides. TAG Heuer's buyers skew heavily iPhone - Merge closes the compatibility gap entirely: notifications, Apple Health sync, contacts, music control, and camera control from a watch that operates in a different category from consumer electronics.
What works with iPhone via Merge
Merge routes every iPhone notification to the Calibre E4 in real time - Messages, email, calendar reminders, third-party apps. Per-app notification controls let you decide what reaches the wrist during a round of golf or a meeting. Health data syncs to Apple Health continuously: heart rate, steps, distance, floors climbed, calories, workouts with GPS routes, and pace all route through Merge's health bridge.
iPhone contacts sync to the watch - the Calibre E4 and the golf app's 40,000-course database make a natural pairing, and having your contacts alongside makes the watch a complete course companion. Music playback and volume are controllable from the watch between holes or during practice. Camera control lets you trigger the iPhone remotely when the camera app is open. The TAG Heuer golf app, the brand-specific watch face collection, and all on-watch features operate independently of phone platform once the watch is set up - the Merge connection handles the iPhone connectivity layer that makes the watch useful every hour of the day.
Android activation note
The Calibre E4's first-time Wear OS setup cannot be completed from an iPhone. You need an Android phone for the initial activation: turn the watch on, pair it to the Android device via Bluetooth, sign into a Google account, and let the watch work through its configuration. Set aside roughly 15 minutes. Once the home screen appears, the Android phone is done and can be returned immediately. The Calibre E4 retains its configuration independently, and Merge connects it to your iPhone permanently from that point on.
Pairing TAG Heuer Calibre E4 with your iPhone
Keep your iPhone and watch within a few feet of each other throughout this process.
- Complete initial Wear OS activation using an Android phone.
- On your iPhone, search the App Store for Merge Watch and install it.
- On the Calibre E4, open Play Store, search for Merge Watch, and install it.
- Open Merge on your iPhone - approve the Bluetooth permission when prompted, then keep it foregrounded.
- On the Calibre E4, open Merge and approve the Bluetooth permission when prompted.
- Tap Start Pairing - the watch stays discoverable for five minutes.
- On your iPhone, open Settings → Bluetooth and wait for the watch to appear in the list, then tap it to pair.
- Once paired, your iPhone will appear in Merge on the watch - tap it to complete the connection.
- Set up your Merge subscription via the iPhone app if prompted.
- Grant notification and health permissions on both devices when asked.
The Calibre E4 as a daily iPhone watch
Once Merge is configured, the Calibre E4 operates as a complete iPhone companion. The OLED panel - 416x416 on the 42mm, 454x454 on the 45mm - is bright and clear under the sapphire crystal. Battery holds around 24 hours, which means nightly charging; for a watch worn in professional environments where evening removal is natural, that rhythm fits. Contacts on the wrist, notification filtering during focused blocks, and camera control for the course round out the daily utility. The ceramic bezel option on the 45mm is one of the few smartwatch materials that genuinely resists the surface wear that accumulates over years of daily use - the color is through the material, not a coating. For iPhone users who want a watch that reads as a serious object on the wrist rather than a fitness accessory, the Calibre E4 is the technically strongest answer in Wear OS.
