Depending on which kit you are using from WiFi Ranger, they are repackaging Mikrotik's Routerboard products. Most Mikrotik products have a pretty wide voltage range they can work off of, the one on my lap says "8VDC-30VDC"...and most of their products will operate on 10V-30VDC. While the common POE voltage is 24VDC, I wonder why WiFi Ranger adds this extra complexity when you could very likely just run the hardware directly off of your
12V power system. Avoiding additional power waste in any voltage transitions that are unnecessary, and reducing failure points.
It is only the SkyPro pack that I don't know what hardware they are using, I don't recognize the hardware that is used for the external unit in the SkyPro...though it is possible it is also a Routerboard just in a custom enclosure.
In the case of the Elite AC it is a Mikrotik Megal AC 52 (retail $119) and probably a hAP AC (retail $50)...but WiFi Ranger is bundling it with software that is a lot more user friendly to configure for this use case than the default Mikrotik platform. This is mostly informational, not trying to badmouth WiFi Ranger as they do add value in that they make this far easier for someone to use.