Coloured scanning electron micrograph (SEM) of Plastic wrap, Glad Press'n Seal. Plastic wrap is a thin plastic film (less than 0.01mm in thickness) that typically is used for sealing food items in containers to keep them fresh. Glad Press'n Seal wrap is a special type of plastic wrap that has its surface covered by shaped, raised pockets (as seen here). The pockets contain an adhesive which is kept away from the background plastic wrap surface. After placing the wrap around a surface (to be sealed) pressure is applied releasing the adhesive and making the surfaces stick together. The adhesive is a special edible type similar to chewing gum. Plastic wrap was first made from PVC (polyvinyl chloride), which remains the most common material, but non-PVC alternatives are now being sold because of concerns about the risk in transfer of plasticizers from PVC into food. Magnification: x10 when shortest axis printed at 25 millimetres.