The RAM-101-RM1U consists of a double socket arm, 2.5" diameter round base with the universal AMPS hole pattern and 3.68" round base. The 3.68" round base contains pre-drilled holes that connect to Raymarine devices listed below. Designed into the mount is a 1.5" 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.