Groppino or Butellina 
They are obtained from the small intestine of the animal, washed, degreased and calibrated immediately after slaughter. For their preservation they are put in salt or brine. It has different calibers (18/20 - 20/22 - 22/24 - 24/26 - 26/28) and quality levels. The product is sold in 70 or 90 meter bundles based on customer demand. In recent years, "ready-to-use" casings have also been sold mounted on rigid or soft plastic tubes which allow to reduce soaking times without losing the quality of the final product.
This type of casing is used for fresh, dried sausage and frankfurters.