The RAM-D-201U-C, short double socket arm, has a socket at both ends that accommodates 2.25 ball bases. A single spring inside the arm opens the end sockets, allowing you to pivot the ball and socket connection. This socket technology allows for almost infinite adjustment and perfect viewing angles. Product Features: Low-profile design with an overall length of 5.1 and socket-to-socket length of 3.6 Attaches to any D size RAM® ball component, including mounting bases and device holders; double ball and socket technology allows for near-infinite adjustability of your RAM® mounting system Made of powder-coated, marine-grade aluminum for durability and reliability in the most demanding environments Backed by a lifetime warranty