RAM Mount 1.5″ Diameter Ball Flat Surface Mount w/2.5″ Round Base & Diamond BaseThe RAM-138U consists of a 2.5″ diameter round base that contains the universal AMPs hole pattern, double socket arm and diamond base adapter. The mount is designed with a 1.5″ diameter patented rubber ball and socket system that has adjustment points at both ends of the double socket arm; this allowing for almost infinite adjustment and perfect viewing angles. The hole pattern found on the diamond base adapter will connect to most RAM cradles. The included RAM’s patented design dampens shock and vibration, helping to extend the life of your device.Overall Height:7.35″ Material: Powder Coated Marine Grade Aluminum Ball Size 1.5″ Rubber Ball Size Note: The “U” in the part number reflects product packaged in poly bag.