This 46cm (18") long stainless steel support rod attaches to the top plate of the Poly-Jaque™ Lab Jack to allow attachment of various clamps and other accessories. The rod diameter is 7.9mm (5/16") and is supplied with two hex nuts for secure attachment to the jack top plate. Clamp Not Included. For buret clamps, see Cat.No. 8-F18204-0000.