"The RAM-D-101-254U consists of a 3.68"" diameter round base, STANDARD length double socket arm and 2.43"" diameter round base. The 3.68"" diameter round base has pre-drilled holes, including two holes at 180 degrees and three holes at 120 degrees. The 2.43"" diameter round base contains the universal AMPs hole pattern. Designed into the mount is a 2.25"" diameter patented rubber ball and socket system with adjustment points at both socket ends of the arm. Rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles."