Vacuum tube's one side is smooth and other is filled with air channels. Channels are necessary for complete air removal and oxygen and moisture blockation. Vacuum tube's are suitable for foodstuff. To make vacuum bags You need vacuum machine, which creates vacuum inside the bag and seals the edges of the tube. To create custom sized bags, measure and cut a piece to your desired length plus 4cm free edges, seal one end, fill the created bag and then seal with vacuum machine. Package contains two rolls, in one roll is 6m.