How do I connect Polar HR monitor to M3i?

M3i and Connecting Heart Rate Monitor

  1.  You'll need to download the polar beat app to activate the Gymlink setting on the Polar H10 chest strap. 
  2. Once you download and open the Polar Beat app, tap on the bottom right corner settings tab.

  3. Under the HR sensor Polar, tap Not Active to pair your Polar H10 strap to the app and slide the enable Gymlink to highlight green.

  4. Once completed, it should appear on the bike screen.

As long as they use a 5 kHz signal it would work. The Polar H1, H7, H9, H10 and T31 Coded Transmitter.

https://support.polar.com/us-en/support/how_to_pair_h7_heart_rate_sensor_with_polar_beat_app_ios