PVC Opstand 100x180 cm Curb type:Splayed curb 35 30 35 cm high for skylight flat roof window 1000 x 1800 Please note! Roof opening = 1300 x 2100 Heatstop Opaal (T) Heatstop Opaal (T) Both the interior and exterior sides are black Tailor the design to your specific project: choose a sloped version to capture the maximum amount of daylight and distribute it evenly throughout the room you choose flawless and completely watertight installation of your skylight or flat roof window