RAM Mount D Size 2.25" Ball on Round Plate w/AMPS Hole PatternD Size 2. 25" Ball on Round Plate with AMPS Hole Pattern The RAM D 254U consists of a 2. 25" diameter rubber ball, connected at right angles to a 2. 4375" diameter round plate. The plate has pre drilled holes in the base plate, including two holes at 180 degrees. Features: Material: Powder Coated Marine Grade Aluminum Ball Size: 2. 25" Rubber Ball "D" Size Note: The "U" in the part number reflects product packaged in poly bag Weight: 0. 6 lbs. RAM