The RAP-340 RAM ROD-2007 is an easy to use fishing rod holder with screw mounted base. Connected directly to the rod holder is a open socket 1.5 inch diameter arm. This socket will allow you to connect to the included 2 x 2.5 inch Rectangular Screw Down Plate.The 1.5 inch ball and socket system lets you move the rod holder into the optimum position whether you have mounted the base vertically, horizontally, or somewhere in between.