The RAM-B-201C RAM Mount Powder Coated Marine Grade Aluminum LONG 5.25'' Double Socket Arm has a socket at either end to allow a 1'' diameter ball accessories to be connected. 

A tightening screw on the side of the arm enables the sockets to clamp firmly to a RAM 1'' diameter ball. When loosening the side screw, a single spring inside the arm opens the sockets allowing you to pivot the ball and socket connection or completely disconnect the ball from the socket.

The arm length is 5.25'' when measured from socket center to socket center.