This motorcycle mount makes attaching to handlebars, tubing, or railing a breeze. Simple to install and easy to use, the possibilities become endless. The zinc coated metal u-bolt and nuts included are designed it fit motorcycle handlebars, or circular rail that are 0.50" to 1.25" in diameter. Rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles. High quality materials insure your iPhone is safe, secure, and within easy reach. RAM’s patented design also dampens shock and vibration helping to extend the life of your mobile device. This mount is designed to hold the following devices: Apple iPhone 4 Material: High Strength Composite & Powder Coated Marine Grade Aluminum Ball Size: 1" Rubber Ball "B" Size