The GS2511KB Carbon 6X Low Level Column Kit from Gitzo is for use with series 2 tripods, and is of intermediate length between the standard center column originally supplied with these tripods, and the very short columns previously supplied as a separate accessory. Its length is designed to provide the lowest shooting angle of the tripod, with the legs not extended but opened to the widest angle.
The kit consists of a 6X-type carbon fiber tube, plus the necessary components for the Ground Level Set feature: a machined aluminum Safe Lock upper disc, redesigned reversible screw, and hook assembly.
This shorter column allows the user to take full advantage of the variable leg spread of the tripod, so that you are not inhibited by the length of the column as to how low to the ground you can go.