The RAM-107U consists of a double socket arm, 2.5" diameter round base with the universal AMPS hole pattern and connecting Humminbird/Apelco marine adapter base. The mount is esigned with a RAM 1.5" diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; this allowing for almost infinite adjustment and perfect viewing angles.Rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles.