The RAM-B-111U-A consists of a short double socket arm, 2.5" diameter round base and 6.25" x 2" 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 Garmin Marine GPS, CB Radios, Ham Radios, Gimbal Brackets and more.