Or, like I said, the bottom of the 99b extension pole. The end on that pole is a female; the post of the clamp I pictured is a male... The extension pole fits over the clamp pole, and you turn the screw on the manfrotto pole (instead of the removable stud that goes into a superclamp, it goes over the post on the clamp I pictured above). The clamp also can fit snugly over any size round bar or rail. It isn't that wide, or heavy. It is big, but it gets a job done that the superclamp cannot.