The RAM-D-111U, powder coated marine grade aluminum mount, consists of a double socket arm mount, one 3-3/4 diameter round base with 2.25 rubber ball and flat 11 x 3 rectangular plate. The plate contains different combinations of pre-drilled holes which will match up to many electronic devices and mounts, including Marine GPS, CB Radios, Ham Radios, Gimbal Brackets and much more. Rubber ball and socket technology dampens shock and vibration, as well as allows for almost infinite adjustment and perfect viewing angles. Ball Size: 2.25 Rubber D Ball Size Material: Powder Coated Marine Grade Aluminum