The RAM-111 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.