Trouble connecting Aftershokz Bluez to Mac

Hi. I just got a pair of Aftershokz Bluez but am having trouble connecting them to my Macbook Pro. They are switched on but the Mac just can't seem to see them. I go to the bluetooth menu but they're not listed.
I remember having a similar problem the first time I tried to connect my Jambox too, and can't remember how I finally got it done.
Is there a trick to this that I'm missing?
I know the headset is working fine because it connected to my iPhone successfully. I've switched bluetooth off on the iPhone to make sure it's not trying to connect to that. But still the Mac won't see the headset.
Any thoughts?