The RAM-D-111-KNOB9HU consists of a 3.68" diameter round base, STANDARD length double socket arm and 11" x 3" rectangular plate. The round base contains pre-drilled holes, including two holes at 180 degrees and three holes at 120 degrees. The rectangle plate contains different combinations of pre-drilled holes which will match up to many electronic devices and mounts, including Marine GPS, CB Radios, Ham Radios, Gimbal Brackets and more. Included with this mount is the RAM Hi-Torq™ Wrench; designed to be used with the knob found on "D" size ball arms and mounts. The wrench matches the shape of the knob and lets you give the arm an extra tight grip. This wrench was originally made for the military when using the RAM mounts in cold weather, and the knob could not be tightened by hand.