I have the Ram Double 6" swing arm with 6.25" X 2" rectangle base and horizontal mounting base. The part # is RAM-109H-1U. They also have a vertical mounting option and a single swing arm unit. That all depends on how much of a reach you need. They are very sturdy and it is just what I needed. The only drawback with Ram is their prices. I have a Humminbird 1198 with a 10.4" screen.