WINS external liquid foil for window insulation window is a ready to use, one-component product forming a vapour-permeable coating (area 1), which regulates the migration of moisture from the window gap to the interior of the building, eliminating foam degradation (area 2). It is chemically neutral and adheres to most construction materials. It creates a flexible and vapour-permeable coating. Due to its flexibility, it is perfect for sealing the joints between the frame and the reveal in WINS systems where usually some displacements occur.