Plastic wrap, cling film (UK), cling wrap or food wrap, is a thin plastic film typically used for sealing food items in containers to keep them fresh over a longer period of time. Plastic wrap, typically sold on rolls in boxes with a cutting edge, clings to many smooth surfaces and can thus remain tight over the opening of a container without adhesive or other devices. Common plastic wrap is roughly 0.5 mils, or 12.5 µm, thick.