RAM Mount Horizontal Single Arm Ball Mount - Gimbal Bracket [RAM-109HSB]RAM Single Arm Ball Mount Horizontal The RAM single swing and socket arm mount includes a 6" STRAIGHT swing arm mounted on a horizontal surface mounting base. At the end of the mount is a rectangular 6. 25" x 2" top base. The pivoting point of the rectangle base allows 180 degree rotation, the swing arm allows a 360 degree rotation. RAM Marine Electronic Mounts Page RAM 109HSB Dimensions A. Center of knob to center of ball socket: 6" B. Overall length