That is correct...ARB Socket holders.
I had a few of them already and they are nice quality, thick material.. and line up to the holes you pre-drilled
You need to use grommets for the wiring and I used silicon 16G for the connection to the socket. You need 90 degree female spades, as well.
The harness is 12g branched into 2 - 16g leads for the sockets over the last 18" (crimped and soldered with marine adhesive wrap)
The USB outlets I am using are Powerwerx..
Powerwerx Panel Mount Combination USB QC3.0 and USB Type-C QC4.0 Fast Device Charger - https://powerwerx.com/panel-usb-qc30-typec-qc40
So far the only ones that can charge my iPad Pro 11" while using Gaia for mapping (and inbuilt GPS/Cellular).
the amazon USB-C ones I have used have worked but when running GPS drain the battery on the iPad. So they cannot keep up with the consumption.
Basically not enough Watts output in the amazon ones...
I'll put the mount to the test with the iPad, so far my Phone has been rock solid.
and so far all the stuff on the dash looks fine, when your driving, you don't really notice it with phone in place.
It would be nice to have AMPS spacing holes pre drilled in the mount though. There is the one in the center but the 2 on the side had to be drilled using the existing RAM 2 hole ones.
Final wiring is waiting on a shipment from AUS with the Voltage relay, which will do all my IGN sensing for the build.