Bloc Blinds blackout skylight blinds are made in the UK to fit VELUX roof windows, also known as skylights or ceiling windows, in lofts, bedrooms, nurseries and home offices. Each blackout roller blind runs in an aluminium cassette with aluminium side channels and brush seals that help block light bleed around the edges, while the white thermal backing helps reflect summer heat and keep warmth in during winter. To find your size, open your window and look for the ID plate on the frame, which shows the window type (for example GGL) and the size code (for example MK04), then choose the matching code from the size menu. Installation needs no drilling, just adhesive tape, 4 screws and a hand screwdriver, and the cord-free spring mechanism lets you set the blind at any height.