Hi! I understand you're having trouble connecting your Macintosh (OS X 10.15) to your two KardiaMobile 6L devices. Let's work through some troubleshooting steps together to get this sorted out.

First, just to clarify:
- Are you using the Kardia app on your Mac or on an iPhone paired to these devices?
- When you try to connect, do you get any error messages or does the app just not detect the devices?
- Have you already tried any troubleshooting steps, like restarting Bluetooth or the devices?

Meanwhile, here’s a basic checklist to start with for connection issues:

1. Bluetooth Enabled: On your Mac, make sure Bluetooth is turned on. You can check this from the menu bar or System Preferences > Bluetooth.

2. Kardia App Permissions: Sometimes, the app needs explicit permission to use Bluetooth. On a Mac, this is usually managed when you install or run the app, but if you’re running the app on a paired iPhone, check that the Kardia app has Bluetooth permission enabled in the phone’s Settings.

3. Pair Device Only Via Kardia App: Importantly, do not try to pair the KardiaMobile 6L manually via the Mac’s Bluetooth settings. Instead, open the Kardia app and let it handle pairing and connecting to the 6L device.

4. Device Proximity and Placement: Keep the Kardia 6L very close to the Mac (within about 1 foot). Also, place your phone or Mac on a stable surface while pairing and connecting.

5. Restart Devices: Turn off Bluetooth, then on again. Restart your Mac and power cycle both Kardia 6L devices (turn them off and back on).

6. Update Kardia App: Ensure your Kardia app is updated to the latest version available for your Mac or paired iPhone.

If you've already tried these, please let me know which ones, and any error details you see. That way, I can suggest more targeted steps or see if we need to explore battery issues or advanced troubleshooting.

Does all this sound doable so far? I’m here to guide you through it!

[Reference: AliveCor Support on KardiaMobile 6L connection checks]1