Two Ubiquiti NanoStation AC loco - one on each building pointing at each other. Turn the power all the way down.
https://www.ubnt.com/airmax/nanostation-ac/
I imagine you'd get 300Mbps+ of real world performance.
https://www.ubnt.com/airmax/nanostation-ac/
I imagine you'd get 300Mbps+ of real world performance.