The pneumatic stopper joint on the Stopper St-Multi connects the machine to a full-volume stopper, used to assemble bags (for stitching with a post-bed sewing machine).
It replicates the internal volume on which the various component parts can be positioned and kept in place by suction applied at the necessary points.
The traditional method makes the manoeuvre to extract the stopper from inside the bag difficult, often damaging the material being processed.