The RAM-149Z-HC1U consists of a zinc coated u-bolt base, double socket arm, 6.35cm (2.5") diameter round base and Rugged Handi-Case^™. Included in this package is hardware that will accommodate rails from 1.27cm (0.50") to 3.18cm (1.25") in diameter. The base includes black cover caps to be placed over the exposed ends of the u-bolt. The included composite rail adapter can narrow the rail to a minimum width of 1.27cm (0.5") . The mount is designed with a RAM 3.81cm (1.5") diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; this allowing for almost infinite adjustment and perfect viewing angles. The RAM Handi-Case^™ is capable of doing so many tasks it will astound you. When a briefcase is too much but a notepad, is not enough, the Handi-Case^™ is exactly what you need. Beyond just a writing surface, you get document storage, tool holder, pen and pencil storage, and of course, RAM's rugged construction. No matter where the job takes you, the RAM Handi-Case^™ is ready to multi task. For any professional on the go this is the tool to keep you organized at home, at the office, or on the go regardless of what you ride, drive, or fly.