This CB antenna ball mount is a versatile mount that attaches to any flat surface and allows you to rotate the ball so that your antenna is vertical, no mater the angle of the mounting surface. You will need access to the opposite site of the mounting surface to tighten the mounting bolts and attach your CB coax. This 4" ball mount is designed to support antennas up to four feet tall. Accepts CB antennas with standard 3/8" x 24 thread studs