The Pole Extensions come with all the parts including clamps and buttons where appropriate. The 3.7 meter has two extensions. The Top Extension (S) and the Handle Extension (M). The 4.9 meter has three extensions. The Top Extension (S) and the Middle Extension (M) and the Handle Extension (L). The 6.3 meter has four extensions. The Top Extension (S) The Middle Extension (M) The Lower Middle Extension (L) and the Handle Extension (LL). 

The extensions from the different length pole saws are specific to that size pole. They are not interchangeable between different length Hayauchi pole saws. The bracketed letters (S) (M) (L) (LL) refer to the circumference of the extension and tell you which size clamp will fit on the pole. All the extensions marked (S) are the same circumference but different lengths for each pole. The same for (M) (L) (LL)