What the Frontier X3 does not carry over

ECG output. The Frontier X2 provides live ECG streaming, ECG PDF download, EDF export and ECG ZIP download. The Frontier X3 provides none of these — it does not display or provide an ECG output at all. Customers who need ECG should use the Frontier X Plus, our FDA-cleared medical device.

This does not affect any metric. Both devices sense the ECG signal continuously, and heart rate, HRV, strain, breathing rate, body shock, step cadence, calories, stress, training load and sleep staging are derived from it on both, with the same accuracy.