When installed the geared center-column replaces the standard platform and provides an additional 48cm of height adjustment. A basic twist lock prevents the column from moving. The geared movement is controlled by a main handle which moves the column vertically up or down in small increments. It has a 3/8"-16 threaded stud on both ends for mounting two tripod heads simultaneously, or for quickly changing your camera's location without removing the arm. Not suitable for TrioPod (TRIOPOD) TrioBalance (TRIOBAL) and TrioBalance = Q 6/8 (TRIOBAL = Q 6/8)!