The RAM-B-139U consists of a 2.5" diameter round base with the universal AMPS hole pattern, double socket arm and 2" x 1.7" square base with the universal AMPS hole pattern. Designed into the mount is a 1" diameter patented rubber ball and socket system with adjustment points at both socket ends of the arm; this with RAM's rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles.