"The RAM-101-LO11 consists of a 2.5"" diameter round base that contains the universal AMPS hole pattern double socket arm and adapter base that inserts directly to the back of Lowrance Elite-5, Mark-5 and Hook-5 Fishfinders. The adapter serves as a quick release mechanism, allowing you to remove or transfer your Fishfinder in seconds. 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; this with RAM's rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles."