RAM Motorcycle Handlebar / Rail Mount and 3" standard arm with RAM-HOL-AP9 Apple iPhone 4 Cradle.
The u-bolt base for attatching to handlebars, tubing, or rails. Simple to install and easy to use, the possibilities become endless. Rubber ball and socket technology allows for almost infinite adjustment and perfect viewing angles. High quality materials insure your device 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.
The RAM handlebar or rail mounts consists of the zinc coated u-bolt, accomodating rails from 1/2" to 1 1/4".(1.3cm - 3.2cm) in diameter. Includes 1 x 26mm & 1 x 32mm u-bolts & adaptor shim.

The video below is an example of a RAM rail mount and may not show your motorcycle or device.