Consists of a zinc coated u-bolt base, double socket arm and universal spring loaded X-Grip cradle Hardware included that will accommodate rails from 0.50" to 1.25" in diameter The base includes black cover caps to be placed over the exposed ends of the u-bolt Composite rail adapter can narrowthe rail to a minimum width of 0.5" The mount is designed with a RAM B size 1" diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; allowing for almost infinite adjustment and perfect viewing angles Spring loaded X-Grip IV cradle expands and contracts, allowing for a perfect custom fit of your phone or phablet Includes a device tether recommended for outdoor applications Minimum Width = 1.875" (Minimum Height = 4.25") Maximum Width = 3.25" (Minimum Height = 2.25") Depth = 0.875"