The RAM-111U consists of a 2.5″ diameter round base that contains the universal AMPs hole pattern, STANDARD LENGTH double socket arm and 6.25″ x 2″ rectangle base. 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. RAM double socket arms with their distinctive Hourglass Shape are designed and recognized to provide the best possible performance for most any application. The Hourglass Shape is a registered trademark of National Products Inc.