"The RAM-231-D-202U consists of a stainless steel u-bolt base, 1.5"" diameter LONG double socket arm and round base adapter that contains the universal AMPs hole pattern. Included in this package is hardware that will accommodate rails from 0.50"" to 1"" in diameter. The base includes black cover aps 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 0.5"". The mount is designed with a RAM 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."