Velux Single Slate Flashing is designed to integrate a Velux roof window into the slate roofing material up to 8mm thick. It ensures that the window is weathertight and stops any leaking. The flashing fits underneath the roofing material with the water being collected in the built-in gutter system. This allows the water to flow smoothly down the side of the window. Suitable for using with roof slates only, it is not suitable for using with interlocking slate and does not come with the installation products