The RAM-D-111-MIU, powder coated marine grade aluminum mount, consists of a double socket arm mount, one 2.5″ 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 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 Note: The „U” in the part number reflects product packaged in poly bag. Drilling may be required to mount to the various gimble brackets. The included plate is a universal mounting bracket with a selection of mounting hole locations. In certain applications additional holes may need to be drilled for proper fit with your electronic device.