Synthetic casings are made from alginates, and the casings themselves require no refrigeration but don't eat the casing, just the tasty sausage inside. Synthetic casings are used by mass producers and can be made in different colors. They are the most uniform and strongest of all types of casings and are most commonly used in salami's. Typically used with sausages that have a longer shelf life than most. All of our synthetic casings come with a 2 fer deal so you can get those crazy internet prices we all love when you buy two.