Among natural casings, there are many sizes, from skinny lamb casings to medium sized to hog casings, to large beef middles. The largest of these is the beef bung, which is the end of the beef's large intestine. These are the "cap ends," which means one side of the casing is the end of the intestine, making it like a long tube sock.

Beef Bung (also known as Beef or Ox Caps) is the cow appendix. Beef Bung is used for large caliber sausages such as mortadella, bologna, salami or coppas. Natural beef bung has a distinctly traditional look and texture.

Beef Bung: The most unfortunate, misleading name for a casing, the “Bung” is not the final stretch of intestines. Actually it is more closely related to an appendix. They also have a capped-end, meaning one end is naturally closed, like a tube-sock.