Food Saver Liquid Block Heat-Seal Barrier Bags Quart. The #1 vacuum sealing system. Keeps liquid away from seal. Keeps food fresh up to 5x longer. Liquid block strip traps moisture. ThickShield bag protection prevents freezer burn. Best performing vacuum storage bag*. Works with: FoodSaver Heat-Seal Vacuum Sealing Systems. Quart size (950 ml).