A stiffening layer for facilitating application of a plastic film to skin, the plastic film being a component in a wound dressing or other medical device and having the stiffening layer removably attached to one side thereof, at least a part of the other side of the film being provided with a layer of self-adhering adhesive. The stiffening layer is made of a stretchable material having a thickness of between 0.5-10 mm. The stiffening layer covers the whole area of the film and is divided into two or more portions by cutting line or lines.
