Ram Mount Rail Base with Stainless Steel U-Bolt and 1-Inch Ball for Rails from 0.5 to 1 Inches Diameter The RAM motorcycle handlebar base contains a 1" rubber ball designed to sit at right angles to the mounting rail The rust proof metal U-bolt accommodates rails in diameter from 0.5" to 1" inches Included are black cover caps to be placed over the exposed ends of the U-bolt Composite adapter that can narrow the rail to a minimum width of 0.5" Powder Coated Marine Grade Aluminum