The RAM-S-D-111 consists of a 3.68" diameter round base, STANDARD LENGTH double socket arm, 11" x 3" rectangular base, RAM mixed combination Pin-Lock™ security nut and key knob. 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 GPS, CB Radios, Ham Radios, Gimbal Brackets and more. RAM® Pin-Lock™ security solutions are designed to withstand the harshest environments where RAM® Mounts are commonly used. With an emphasis on aesthetics and function, RAM® security nuts/knobs are low profile and only add a small amount of additional bulk to your system when compared to the standard knob included. At a fraction of the cost of currently available keyed locking knobs, the additional peace of mind and tamper resistance comes at a very affordable price.