The RAP-111U consists of a 2" x 1.7" 2" x 1.7" square 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.