The RAP-B-202-LO11-354-TRA1U consists of a Track Ball base, composite 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. A key feature of the mount is a 1" diameter rubber ball and socket system with adjustment points at both socket ends of the arm. Combined with RAM's rubber ball and socket technology, this allows for high adjustibility to achieve perfect viewing angles. Compatible with virtually any track system including the RAM Tough-Track. T-Bolt Dimensions: .48" x .95" Overall Length: 5"