RAM Heavy Duty Marine Mount w Standard Arm D (RAM-D-111U)Included: 1 x RAM Heavy Duty Marine Mount w Standard Arm (RAM D 111U) The RAM D 111U consists of a standard double socket arm (D Size), 3. 68" diameter round base and 11" x 3" rectangular base. The round base contains pre drilled holes, including two holes at 180 degrees and three holes at 120 degrees. The rectangle base contains different combinations of pre drilled holes which will match up to many electronic devices and mounts, including Marine