Originally Posted by
JohnJ80
If it has to connect to the iPad, you will need either a HRM that support bluetooth or the NPE dongle that converts ANT+ to BT.
To clarify, the HRM you get has to be compatible with your iPad, not with Zwift. Usually that's not an important distinction, but folks have different levels of familiarity with computer tech, so maybe putting it this way will help.
John told you exactly what you need.
If I was going to buy a new one I'd want a Wahoo or 4iiii that you can use with a phone or iPad and also with a Garmin.