RAM Zinc Coated U-Bolt Mounting Base with 1 inch Ball The RAM motorcycle handlebar base contains a 1" rubber ball designed to sit at right angles to the mounting rail The zinc coated metal U-bolt accommodates rails in diameter from 0.5" to 1.25" 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