The RAM-B-101-LO11 consists of a 2.5" diameter round base with the universal AMPS hole pattern double socket arm and adapter base that inserts directly to the back of Lowrance Elite-4 Mark-4 and Hook-4 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" 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.