Which 3rd Party Bluetooth Adapter for old iMac

Zwift kept crashing my MacBook Pro so I’m going back to my old 2011 iMac.
I have an ANT+ dongle that is working with the iMac, however I can’t get my RR SmartTrainer to work in Zwift. Can anyone tell me which Bluetooth (BLE) adapter I should buy to get it working?

Thanks all - B

Try this one. I’m not 100% certain, but it’s recommended by Hackintosh sites as a 3rd party bluetooth adapter that works without having to install any drivers. I’ve got one by Pluggable that has the same Broadcom chip inside. https://www.amazon.com/dp/B007MKMJGO/