RAM Mounts Rail U-Bolt Base With 1 Ball Mount The RAM Mount U-Bolt handlebar base features a 1 rubber ball positioned perpendicular to the mounting rail. It comes with black cover caps for the u-bolt ends. The black aluminum and stainless steel variants include a composite adapter to adjust the rail width to a minimum of 0.5. U-Bolt Dimensions: Black version accommodates rails from 0.5 to 1.25 in diameter Chrome version accommodates rails from 0.5 to 1 in diameter Stainless Steel version accommodates rails from 0.5 to 1 in diameter Material: Powder Coated Marine Grade Aluminum or Powder Coated Marine Grade Aluminum with Chrome Finish Stainless Steel with natural finish Ball Size: 1 Rubber Ball B Size