The Chrome Plated Marine Grade Aluminum Universal Plate has a 1.0" diameter Rubber Ball connected at right angles to a 1 1/4" x 2 1/2" Diamond Plate. The plate has two pre-drilled holes positioned at either tip of the diamond plate. The plate can be used as a mounting plate or to attach to any of the RAM plastic HOL holders and the industry standard AMPS hole pattern. The ""U"" in the part number reflects product packaged in poly bag. For additional specifications, see components and drawings tabs.Powder Coated Marine Grade AluminumChrome Finish1 Inch Rubber Ball