A sheet of plastic material designed to be placed over a wound dressing (e.g. open-cell foam or medicated gauze) to create a complete occlusion over and around a wound during negative pressure wound therapy (NPWT). This film dressing is typically vapour permeable, waterproof, and has an adhesive backing or edges applied against the wound dressing and surrounding healthy skin to create an airtight seal; it may be impregnated/coated with a gel (e.g., silicone) to minimize risk of trauma upon removal. It has a central opening, or an opening is made in or under it, to enable placement of the drain allowing negative pressure to reach the wound through the dressing. This is a single-use device.