The RAM-D-101-RM1U consists of a 3.68" diameter round base with the universal AMPS hole pattern, STANDARD length double socket arm and 3.68" round base. The RAM-D-101-RM1U includes hardware that will attach Raymarine Chartplotters to the mount. 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.