So you need two of them...???
No they come as a pair and already setup to talk to each other. It was really easy to setup.
But I think just putting down ethernet, that short of a run is super easy.
They come in a pair. I used to install these down in florida. Good stuff but you could get away with the nanostation? or loco. cant remember the name of the model but is a lot cheaper.
I never liked Unifis other products for point to point wireless. They typically break any mdns, these don't IIRC.