In mailing lines the position of the folding unit always changes. Sometimes at the beginning, in the middle or at the end. Depending on the units next to the folding unit, a height adjustment is always necessary. Also a self-drive and self-control must be part of the folding unit to run them as a stand-alone unit. Available are different working widths and number of pockets. Therefore, many typical mailing equipment like additional cutter shafts or segmented folding rollers are available.