CLIPS of Aluminum have long been respected for polypropylene bag closure. Also used for either natural or artificial sausage casings as well as nets that hold vegetables and fruits. They are even known to be used for fluid filled bags (live fish transport). Strips holding 50 of these "713 series staples" (CLIPS) are fed through a manually operated machine with an Arm Lever that is pulled to CLINCH the fairly soft aluminum legs over tightly. Clips are available in two sizes, 7/16" and 1/2".