The powder coated marine grade Aluminum base consists of a 2.25" diameter rubber ball, connected at right angles to a 3.68" diameter round base. The base has pre-drilled holes, including two holes at 180 degrees and three holes at 120 degrees.Material: Powder Coated Marine Grade AluminumBall Size: 2.25" Rubber Ball "D" SizeManufacturer Part Number:RAM-D-202U