Chest straps are accurate but uncomfortable for many athletes — especially during weight training, hybrid workouts, or long efforts. The COROS HRM sits on your bicep rather than your chest, which gives you a more secure, skin-contact fit than a wrist-based watch while avoiding the compression and chafing of a chest strap. It weighs just 9.7g, so most athletes forget they're wearing it after the first few minutes.

It connects via Bluetooth to up to 3 devices simultaneously — including COROS watches, Garmin watches, bike computers, indoor trainers, and Bluetooth-enabled gym equipment. It also works with third-party apps like Strava and TrainingPeaks. Note: the COROS HRM uses Bluetooth only and does not support ANT+, so it won't pair with older devices (like some Garmin Forerunner models) that require ANT+ for heart rate sensors.

The COROS HRM offers 38 hours of continuous active use and 80 days in standby on a single charge. Recharging takes under 2 hours via the magnetic USB cable. You can check battery level through the COROS app, on a connected COROS watch, or via the LED indicator on the device itself.

The standard band fits bicep circumferences of 7.09–12.6 inches (18–32cm). A large size is also available for circumferences of 9.4–16.9 inches (24–43cm). The elastic band adjusts via a sliding buckle for a snug, custom fit, and the velcro enclosure makes it easy to remove and wash the band.