Why we picked it
Anyone who wants gold-standard heart rate accuracy for interval training, zone work or checking a watch’s optical sensor
What to know before you buy
A chest strap is less comfortable than an arm band, needs sweat or moisture for a clean signal in the first minutes, and only stores a single workout; the Polar Flow app gets mixed reviews
Key specs
- ECG-based chest sensor; DC Rainmaker uses it as the reference strap in its own accuracy testing and Garage Gym Reviews rates accuracy 5/5
- Connectivity: ANT+ (unlimited), 2 concurrent Bluetooth connections, plus 5 kHz Gymlink for gym equipment
- Replaceable CR2025 coin cell, roughly 400 hours / about 1 year of typical use
- Onboard memory stores one workout for phone-free sessions
- Waterproof, swim-safe; Pro Strap with anti-slip dots, two strap sizes
- Works with Polar Beat/Flow and 200+ third-party apps (Zwift, Peloton, Strava, Garmin, Apple)
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