The RAM-120-231 consists of a "rust-proof" stainless steel u-bolt base, double socket arm and universal side clamping holder. Included in this package is hardware that will accommodate rails from 1.27cm (0.5") to 2.54cm (1") 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 side clamping holder can expand and contract, securing your device for a custom fit.