The RAM-B-149Z-C-347U consists of a zinc coated u-bolt base, LONG double socket arm and square adapter base that contains the universal AMPs hole pattern.. 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 included composite rail adapter can narrow the rail to a minimum width of 0.5″. The square adapter base contains four pre-drilled holes at each corner, making the universal 1.5 x 1.188 (hole spacing) AMPS hole pattern. 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. This mount is designed to hold the following devices: Garmin® zumo™ 400 Garmin® zumo™ 450 Garmin® zumo™ 500 Garmin® zumo™ 550 Garmin® zumo™ 660 TomTom Rider 2 TomTom Urban Rider U-Bolt Dimensions: 0.50″ to 1.25″ Material: Powder Coated Marine Grade AluminumBall Size: 1″ Rubber Ball „B” Size Note: The „U” in the part number reflects product packaged in poly bag. Related Links:RAM GPS MountsRAM Motorcycle Mounts.