This C size short double socket arm includes a RAM Pin-Lock locking knob for theft deterrence. The socket arm consists of a 1.5" diameter socket size compatible with C size ball bases and adapters. RAM Pin-Lock security solutions are designed to withstand the harshest environments and keep devices locked to the mounting area; perfect for tablet mounts, fishfinder mounts and other larger devices. 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 traditional key locking knobs, the additional peace of mind and tamper resistance comes at a very affordable price.