Collagen Casings take the place of using natural hog or sheep casings. They can be used for fresh or smoked sausages. They are made from beef protein. There is no preparation necessary. Just put them on your stuffing tube and before you know it, you will have uniformly sized sausages! Use the 32mm size for Brats or Italian links. The 21mm size are great for breakfast sausage. 19mm and 17mm are snack stick size.(Remember you will need a 1/2" O.D. tube or smaller for these.) Buy 3 or more of the same Item # & SAVE. (Caddies not included). Discount taken in cart. Approximate stuffed weight: 32mm - 21 lbs. 21mm - 20 lbs. 24mm - 13 lbs. 19mm - 14 lbs. 17mm - 13 lbs.