This is our FDBASE-ML. It is the mounting base for the Military arm.
This is screwed directly into the wall/location where the arm and display are to be mounted. You’ll notice the 4 holes on the front of the raised section. This is where the Military arm screws into the base itself.
In this picture you can see how those come together. They are not just locked into each other, but firmly screwed together with 4 screws, so they are very secure.