Pouches come in two basic styles: heat-sealed and self-sealed. The most common pouch used in sterile processing departments is the heat-sealed pouch. After the instruments are placed into a pouch, heat is applied to the open side to fuse the pouch together. Heat seal pouches are an economical solution and are available in a flat pouch, a gusseted pouch and roll tubing. Flat pouches consist of two pieces of material that have been sealed on three sides.