Simple to install and easy to use, the RAM U-Bolt Mount Base attaches to handlebars, tubing, or railing with little effort. Rubber ball-and-socket technology allows for a wide range of adjustment and perfect viewing angles. High-quality powder-coated Marine grade aluminum ensures your device is safe, secure, and accessible. Dampens shock and vibration helping to extend the life of your mobile device. Includes hardware that accommodates rails from 0.50" to 1.25" in diameter. 1" rubber ball, "B" size. 1"" rubber ball, ""B"" size Dampens shock & vibration High-quality powder-coated aluminum construction