The Spindle Cappers and certain specialty cappers use gripper belts to stabilize containers as they move through the capping machine.  The gripper belt assembly comes standard with a 3/4" neoprene gripping surface, but other belt materials and sizes are available. 

The gripper belts on the capping machines can be adjusted up and down as needed to stabilize different container sizes and shapes.  In addition, the spindle cappers allow for easy width adjustments to handle thin and wide containers.

For odd shaped containers a double gripper belt assembly can be added to the spindle capper or specialty cappers for additional support and stability.