RAM Mounts X-Grip Handlebar U-Bolt Base The The Ram-B-149Z-Un7U and Ram-B-149Z-Un10U consists of a zinc coated u-bolt base, double socket arm and universal X-Grip cradle. Included in this package is hardware 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. The mount is designed with a RAM 1 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. Features: The included composite rail adapter can narrow the rail to a minimum width of 0.5 The included X-Grip cradle has a clean and clever four leg design that sports great holding power without hiding your phone behind foam pads and plastic The spring loaded X-Grip cradle expands and contracts, allowing for a perfect custom fit of your cell phone and includes a device tether recommended for rugged applications The X-Grip holder is compatible with handheld devices that will fit the dimensions listed below. It is important to verify the dimensions of your handheld device with a case/sleeve/skin when determining the overall size. Small X-Grip Holder Dimensions: Width Range 1.875 to 3.25 Depth 0.875 max Large X-Grip Holder Dimensions: Minimum Width 1.75 to 4.5 Depth 0.875 max Material: High Strength Composite, Rubber Tips, Powder Coated Marine Grade Aluminum and Stainless Steel Construction Ball Size: 1 Rubber Ball B Size