Just noticed a good deal for anyone chasing one of these units, that are highly recommended by the majority of reviewers who have them! This bundle is especially good if you don't have a compatible bike computer as this bundle comes with a head unit. Cheaper than the old models that are still floating around out there.
The newer RTL515 is also available (though you may get a better deal on the unit by itself elsewhere) if you have an existing compatible device to use for the radar read out:
https://www.wiggle.com.au/garmin-varia-rearview-bike-radar-r…
From my brief research, it seems like one of the only differences between the 510 in the bundle and the newer 515 is the latter has BLE for connecting to smartphones.
Great technology for extra safety and peace of mind for road cyclists. I can't wait to start using mine!
As per the description, if you already have a Garmin/Wahoo/etc, you will be better off getting the newer model. The RTL515.
So the Garmin/Wahoo/etc becomes the head unit and you wont need the head unit.
I have seen them as cheap as around $290 give or take
https://www.amazon.com.au/Garmin-Cycling-Rearview-Audible-Ve…