The RAM-238U consists of a 1.5" diameter rubber ball connected at right angles to a 2.43" x 1.31" diamond base. The base has two holes 1.912" from center to center, matches the industry standard AMPS hole pattern and will connect to a large variety of RAM Mount and third party cradles.Material:Powder Coated Marine Grade AluminumBall Size:1.5" Rubber Ball SizeNote:The "U" in the part number reflects product packaged in poly bag.