RAM MOUNTS' RAM-B-111U consists of a double socket arm, 2.5 in diameter round base and 6.25 in x 2 in rectangle base. The round base contains pre-drilled holes, including the universal AMPS hole pattern. The rectangle base 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.