strenkarosa Yes, all of our Mahogany Firbous Summer Sausage Casings are pre-stuck, we have 1 clear (https://www.waltonsinc.com/2-9-x-20-clear-fibrous-summer-sausage-casings that isnt). They are tiny little holes that are in the casing which allows for pressure to escape during the cooking process and lets the casing form to the meat tighter.